Multi-field charged particle cancer therapy method and apparatus

ABSTRACT

The invention comprises a multi-field charged particle irradiation method and apparatus. Radiation is delivered through an entry point into the tumor and Bragg peak energy is targeted to a distal or far side of the tumor from an ingress point. Delivering Bragg peak energy to the distal side of the tumor from the ingress point is repeated from multiple rotational directions. Preferably, beam intensity is proportional to radiation dose delivery efficiency. Preferably, the charged particle therapy is timed to patient respiration via control of charged particle beam injection, acceleration, extraction, and/or targeting methods and apparatus. Optionally, multi-axis control of the charged particle beam is used simultaneously with the multi-field irradiation. Combined, the system allows multi-field and multi-axis charged particle irradiation of tumors yielding precise and accurate irradiation dosages to a tumor with distribution of harmful irradiation energy about the tumor.

CROSS REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of:

-   -   U.S. provisional patent application No. 61/055,395 filed May 22,        2008;    -   U.S. provisional patent application No. 61/137,574 filed Aug. 1,        2008;    -   U.S. provisional patent application No. 61/192,245 filed Sep.        17, 2008;    -   U.S. provisional patent application No. 61/055,409 filed May 22,        2008;    -   U.S. provisional patent application No. 61/203,308 filed Dec.        22, 2008;    -   U.S. provisional patent application No. 61/188,407 filed Aug.        11, 2008;    -   U.S. provisional patent application No. 61/209,529 filed Mar. 9,        2009;    -   U.S. provisional patent application No. 61/188,406 filed Aug.        11, 2008;    -   U.S. provisional patent application No. 61/189,815 filed Aug.        25, 2008;    -   U.S. provisional patent application No. 61/208,182 filed Feb.        23, 2009;    -   U.S. provisional patent application No. 61/201,731 filed Dec.        15, 2008;    -   U.S. provisional patent application No. 61/208,971 filed Mar. 3,        2009;    -   U.S. provisional patent application No. 61/205,362 filed Jan.        21, 2009;    -   U.S. provisional patent application No. 61/134,717 filed Jul.        14, 2008;    -   U.S. provisional patent application No. 61/134,707 filed Jul.        14, 2008;    -   U.S. provisional patent application No. 61/201,732 filed Dec.        15, 2008;    -   U.S. provisional patent application No. 61/198,509 filed Nov. 7,        2008;    -   U.S. provisional patent application No. 61/134,718 filed Jul.        14, 2008;    -   U.S. provisional patent application No. 61/190,613 filed Sep. 2,        2008;    -   U.S. provisional patent application No. 61/191,043 filed Sep. 8,        2008;    -   U.S. provisional patent application No. 61/192,237 filed Sep.        17, 2008,    -   U.S. provisional patent application No. 61/201,728 filed Dec.        15, 2008;    -   U.S. provisional patent application No. 61/190,546 filed Sep. 2,        2008;    -   U.S. provisional patent application No. 61/189,017 filed Aug.        15, 2008;    -   U.S. provisional patent application No. 61/198,248 filed Nov. 5,        2008;    -   U.S. provisional patent application No. 61/198,508 filed Nov. 7,        2008;    -   U.S. provisional patent application No. 61/197,971 filed Nov. 3,        2008;    -   U.S. provisional patent application No. 61/199,405 filed Nov.        17, 2008;    -   U.S. provisional patent application No. 61/199,403 filed Nov.        17, 2008;    -   U.S. provisional patent application No. 61/199,404 filed Nov.        17, 2008; and        claims priority to PCT patent application no. PCT/RU2009/00105,        “Multi-Field Charged Particle Cancer Therapy Method and        Apparatus”, filed Mar. 4, 2009;    -   all of which are incorporated herein in their entirety by this        reference thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to treatment of solid cancers. Moreparticularly, the invention relates to charged particle irradiation beamcontrol in cancer therapy.

2. Discussion of the Prior Art

Cancer Treatment

Several distinct forms of radiation therapy exist for cancer treatmentincluding: brachytherapy, traditional electromagnetic X-ray therapy, andproton therapy. Proton therapy systems typically include: a beamgenerator, an accelerator, and a beam transport system to move theresulting accelerated protons to a plurality of treatment rooms wherethe protons are delivered to a tumor in a patient's body.

Proton therapy works by aiming energetic ionizing particles, such asprotons accelerated with a particle accelerator, onto a target tumor.These particles damage the DNA of cells, ultimately causing their death.Cancerous cells, because of their high rate of division and theirreduced ability to repair damaged DNA, are particularly vulnerable toattack on their DNA.

Charged Particle Cancer Therapy

Patents related to the current invention are summarized here.

Proton Beam Therapy System

F. Cole, et. al. of Loma Linda University Medical Center “Multi-StationProton Beam Therapy System”, U.S. Pat. No. 4,870,287 (Sep. 26, 1989)describe a proton beam therapy system for selectively generating andtransporting proton beams from a single proton source and accelerator toa selected treatment room of a plurality of patient treatment rooms.

Gantry

T. Yamashita, et. al. “Rotating Irradiation Apparatus”, U.S. Pat. No.7,381,979 (Jun. 3, 2008) describe a rotating gantry having a front ringand a rear ring, each ring having radial support devices, where theradial support devices have linear guides. The system has thrust supportdevices for limiting movement of the rotatable body in the direction ofthe rotational axis of the rotatable body.

T. Yamashita, et. al. “Rotating Gantry of Particle Beam Therapy System”U.S. Pat. No. 7,372,053 (May 13, 2008) describe a rotating gantrysupported by an air braking system allowing quick movement, braking, andstopping of the gantry during irradiation treatment.

M. Yanagisawa, et. al. “Medical Charged Particle Irradiation Apparatus”,U.S. Pat. No. 6,992,312 (Jan. 31, 2006); M. Yanagisawa, et. al. “MedicalCharged Particle Irradiation Apparatus”, U.S. Pat. No. 6,979,832 (Dec.27, 2005); and M. Yanagisawa, et. al. “Medical Charged ParticleIrradiation Apparatus”, U.S. Pat. No. 6,953,943 (Oct. 11, 2005) alldescribe an apparatus capable of irradiation from upward and horizontaldirections. The gantry is rotatable about an axis of rotation where theirradiation field forming device is eccentrically arranged, such that anaxis of irradiation passes through a different position than the axis ofrotation.

H. Kaercher, et. al. “Isokinetic Gantry Arrangement for the IsocentricGuidance of a Particle Beam And a Method for Constructing Same”, U.S.Pat. No. 6,897,451 (May 24, 2005) describe an isokinetic gantryarrangement for isocentric guidance of a particle beam that can berotated around a horizontal longitudinal axis.

G. Kraft, et. al. “Ion Beam System for Irradiating Tumor Tissues”, U.S.Pat. No. 6,730,921 (May 4, 2004) describe an ion beam system forirradiating tumor tissues at various irradiation angles in relation to ahorizontally arranged patient couch, where the patient couch isrotatable about a center axis and has a lifting mechanism. The systemhas a central ion beam deflection of up to ±15 degrees with respect to ahorizontal direction.

M. Pavlovic, et. al. “Gantry System and Method for Operating Same”, U.S.Pat. No. 6,635,882 (Oct. 21, 2003) describe a gantry system foradjusting and aligning an ion beam onto a target from a freelydeterminable effective treatment angle. The ion beam is aligned on atarget at adjustable angles of from 0 to 360 degrees around the gantryrotation axis and at an angle of 45 to 90 degrees off of the gantryrotation axis yielding a cone of irradiation when rotated a fullrevolution about the gantry rotation axis.

Movable Patient

N. Rigney, et. al. “Patient Alignment System with External Measurementand Object Coordination for Radiation Therapy System”, U.S. Pat. No.7,199,382 (Apr. 3, 2007) describe a patient alignment system for aradiation therapy system that includes multiple external measurementdevices that obtain position measurements of movable components of theradiation therapy system. The alignment system uses the externalmeasurements to provide corrective positioning feedback to moreprecisely register the patient to the radiation beam.

Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S.Pat. No. 7,030,396 (Apr. 18, 2006); Y. Muramatsu, et. al. “MedicalParticle Irradiation Apparatus”, U.S. Pat. No. 6,903,356 (Jun. 7, 2005);and Y. Muramatsu, et. al. “Medical Particle Irradiation Apparatus”, U.S.Pat. No. 6,803,591 (Oct. 12, 2004) all describe a medical particleirradiation apparatus having a rotating gantry, an annular frame locatedwithin the gantry such that it can rotate relative to the rotatinggantry, an anti-correlation mechanism to keep the frame from rotatingwith the gantry, and a flexible moving floor engaged with the frame insuch a manner to move freely with a substantially level bottom while thegantry rotates.

H. Nonaka, et. al. “Rotating Radiation Chamber for Radiation Therapy”,U.S. Pat. No. 5,993,373 (Nov. 30, 1999) describe a horizontal movablefloor composed of a series of multiple plates that are connected in afree and flexible manner, where the movable floor is moved in synchronywith rotation of a radiation beam irradiation section.

Patient Positioning

Y. Nagamine, et. al. “Patient Positioning Device and Patient PositioningMethod”, U.S. Pat. No. 7,212,609 (May 1, 2007) and Y. Nagamine, et. al.“Patient Positioning Device and Patient Positioning Method”, U.S. Pat.No. 7,212,608 (May 1, 2007) describe a patient positioning system thatcompares a comparison area of a reference X-ray image and a currentX-ray image of a current patient location using pattern matching.

D. Miller, et. al. “Modular Patient Support System”, U.S. Pat. No.7,173,265 (Feb. 6, 2007) describe a radiation treatment system having apatient support system that includes a modularly expandable patient podand at least one immobilization device, such as a moldable foam cradle.

K. Kato, et. al. “Multi-Leaf Collimator and Medical System IncludingAccelerator”, U.S. Pat. No. 6,931,100 (Aug. 16, 2005); K. Kato, et. al.“Multi-Leaf Collimator and Medical System Including Accelerator”, U.S.Pat. No. 6,823,045 (Nov. 23, 2004); K. Kato, et. al. “Multi-LeafCollimator and Medical System Including Accelerator”, U.S. Pat. No.6,819,743 (Nov. 16, 2004); and K. Kato, et. al. “Multi-Leaf Collimatorand Medical System Including Accelerator”, U.S. Pat. No. 6,792,078 (Sep.14, 2004) all describe a system of leaf plates used to shortenpositioning time of a patient for irradiation therapy. Motor drivingforce is transmitted to a plurality of leaf plates at the same timethrough a pinion gear. The system also uses upper and lower aircylinders and upper and lower guides to position a patient.

Problem

There exists in the art of particle beam therapy of cancerous tumors aneed for charged particle irradiation beam control. More particularly,there exists in the art a need for efficient delivery of chargedparticles to the tumor, where efficiency is the fraction of energydeposited in the tumor relative to the fraction of energy deposited inhealthy tissue.

SUMMARY OF THE INVENTION

The invention comprises a multi-field charged particle irradiation beammethod and apparatus used in radiation therapy of cancerous tumors.

DESCRIPTION OF THE FIGURES

FIG. 1 illustrates component connections of a particle beam therapysystem;

FIG. 2 illustrates a charged particle therapy system;

FIG. 3 illustrates an ion beam generation system;

FIG. 4 illustrates straight and turning sections of a synchrotron;

FIG. 5 illustrates bending magnets of a synchrotron;

FIG. 6 provides a perspective view of a bending magnet;

FIG. 7 illustrates a cross-sectional view of a bending magnet;

FIG. 8 illustrates a cross-sectional view of a bending magnet;

FIG. 9 illustrates a magnetic turning section of a synchrotron;

FIGS. 10A and B illustrate an RF accelerator and an RF acceleratorsubsystem, respectively;

FIG. 11 illustrates a magnetic field control system;

FIG. 12 illustrates a charged particle extraction and intensity controlsystem;

FIG. 13 illustrates a proton beam position verification system;

FIG. 14 illustrates a patient positioning system from: (A) a front viewand (B) a top view;

FIG. 15 provides X-ray and proton beam dose distributions;

FIGS. 16 A-E illustrate controlled depth of focus irradiation;

FIGS. 17 A-E illustrate multi-field irradiation;

FIG. 18 illustrates dose efficiency enhancement via use of multi-fieldirradiation;

FIGS. 19A-C and FIG. 19E illustrate distal irradiation of a tumor fromvarying rotational directions and FIG. 19D illustrates integratedradiation resulting from distal radiation;

FIG. 20 provides two methods of multi-field irradiation implementation;

FIG. 21 illustrates multi-dimensional scanning of a charged particlebeam spot scanning system operating on: (A) a 2-D slice or (B) a 3-Dvolume of a tumor;

FIG. 22 illustrates an electron gun source used in generating X-rayscoupled with a particle beam therapy system;

FIG. 23 illustrates an X-ray source proximate a particle beam path;

FIG. 24 illustrates a semi-vertical patient positioning system;

FIG. 25 illustrates respiration monitoring;

FIG. 26 illustrates a patient positioning, immobilization, andrepositioning system;

FIG. 27 shows particle field acceleration timed to a patient'srespiration cycle; and

FIG. 28 illustrates adjustable particle field acceleration timing.

DETAILED DESCRIPTION OF THE INVENTION

The invention comprises a multi-field charged particle irradiation beammethod and apparatus used in radiation therapy of cancerous tumors.

In one embodiment, a method and apparatus for efficient radiation dosedelivery to a tumor is described. Preferably, radiation is deliveredthrough an entry point into the tumor and Bragg peak energy is targetedto a distal or far side of the tumor from an ingress point. DeliveringBragg peak energy to the distal side of the tumor from the ingress pointis repeated from multiple rotational directions. Beam intensity isproportional to radiation dose delivery efficiency. The multi-fieldirradiation process with energy levels targeting the far side of thetumor from each irradiation direction provides even and efficientcharged particle radiation dose delivery to the tumor. Preferably, thecharged particle therapy is timed to patient respiration via control ofcharged particle beam injection, acceleration, extraction, and/ortargeting methods and apparatus.

For example, radiation is delivered through an entry point into thetumor and Bragg peak energy is targeted to a distal or far side of thetumor from an ingress point. Delivering Bragg peak energy to the distalside of the tumor from the ingress point is repeated from multiplerotational directions. Preferably, beam intensity is proportional toradiation dose delivery efficiency. Preferably, the charged particletherapy is timed to patient respiration via control of charged particlebeam injection, acceleration, extraction, and/or targeting methods andapparatus. Optionally, multi-axis control of the charged particle beamis used simultaneously with the multi-field irradiation. Combined, thesystem allows multi-field and multi-axis charged particle irradiation oftumors yielding precise and accurate irradiation dosages to a tumor withdistribution of harmful ingress energy about the tumor.

In another embodiment, the system relates to a combined rotation/rastermethod and apparatus, referred to as multi-field charged particle cancertherapy. The system uses a fixed orientation charged particle source,such as a proton source, relative to a rotating patient to yield tumorirradiation from multiple directions. Preferably, the system combineslayer-wise tumor irradiation from many directions with controlled energyproton irradiation to deliver peak proton beam energy within a selectedtumor volume or irradiated slice. Optionally, the selected tumor volumefor irradiation from a given angle is a distal portion of the tumor. Inthis manner ingress Bragg peak energy is circumferentially spread aboutthe tumor minimizing damage to healthy tissue and peak proton energy isefficiently, accurately, and precisely delivered to the tumor.

In yet another embodiment, a multi-field imaging and a multi-fieldcharged particle cancer therapy method and apparatus is used that iscoordinated with patient respiration via use of feedback sensors used tomonitor and/or control patient respiration. Optionally, the respirationmonitoring system uses thermal and/or force sensors to determine where apatient is in a respiration cycle in combination with a feedback signalcontrol delivered to the patient to inform the patient when breathcontrol is required. Preferably, the multi-field imaging, such as X-rayimaging, and the charged particle therapy are performed on a patient ina partially immobilized and repositionable position. X-ray and/or protondelivery is timed to patient respiration via control of charged particlebeam injection, acceleration, extraction, and/or targeting methods andapparatus.

In still yet another embodiment, a multi-axis charged particleirradiation method and apparatus is described, optionally used incombination with multi-field irradiation. The multi-axis controlsincludes separate control of one or more of horizontal or x-axisposition, vertical or y-axis position, energy control, and intensitycontrol of the charged particle irradiation beam. Optionally, theseparate control is independent control. Optionally, the chargedparticle beam is additionally controlled in terms of timing. Timing iscoordinated with patient respiration and/or patient rotationalpositioning. Combined, the system allows multi-axis and multi-fieldcharged particle irradiation of tumors yielding precise and accurateirradiation dosages to a tumor with distribution of harmful healthytissue volume ingress energy about the tumor.

In another embodiment, the system uses a radio-frequency (RF) cavitysystem to induce betatron oscillation of a charged particle stream.Sufficient amplitude modulation of the charged particle stream causesthe charged particle stream to hit a material, such as a foil. The foildecreases the energy of the charged particle stream, which decreases aradius of curvature of the charged particle stream in the synchrotronsufficiently to allow a physical separation of the reduced energycharged particle stream from the original charged particle stream. Thephysically separated charged particle stream is then removed from thesystem by use of an applied field and deflector.

In still another embodiment, the system comprises intensity control of acharged particle beam acceleration, extraction, and/or targeting methodand apparatus used in conjunction with charged particle beam radiationtherapy of cancerous tumors. Particularly, intensity of a chargedparticle stream of a synchrotron is described in combination withturning magnets, edge focusing magnets, concentrating magnetic fieldmagnets, winding and control coils, and extraction elements of thesynchrotron. The system reduces the overall size of the synchrotron,provides a tightly controlled proton beam, directly reduces the size ofrequired magnetic fields, directly reduces required operating power, andallows continual acceleration of protons in a synchrotron even during aprocess of extracting protons from the synchrotron.

Used in combination with the invention, novel design features of acharged particle beam cancer therapy system are described. Particularly,a negative ion beam source with novel features in the negative ionsource, ion source vacuum system, ion beam focusing lens, and tandemaccelerator is described. Additionally, turning magnets, edge focusingmagnets, magnetic field concentration magnets, winding and correctioncoils, flat magnetic field incident surfaces, and extraction elementsare described that minimize the overall size of the synchrotron, providea tightly controlled proton beam, directly reduce the size of requiredmagnetic fields, directly reduce required operating power, and allowcontinual acceleration of protons in a synchrotron even during a processof extracting protons from the synchrotron. The ion beam source systemand synchrotron are preferably computer integrated with a patientimaging system and a patient interface including respiration monitoringsensors and patient positioning elements. Further, intensity control ofa charged particle beam acceleration, extraction, and/or targetingmethod and apparatus used in conjunction with charged particle beamradiation therapy of cancerous tumors is described. More particularly,intensity, energy, and timing control of a charged particle stream of asynchrotron is described. The synchrotron control elements allow tightcontrol of the charged particle beam, which compliments the tightcontrol of patient positioning to yield efficient treatment of a solidtumor with reduced tissue damage to surrounding healthy tissue. Inaddition, the system reduces the overall size of the synchrotron,provides a tightly controlled proton beam, directly reduces the size ofrequired magnetic fields, directly reduces required operating power, andallows continual acceleration of protons in a synchrotron even during aprocess of extracting protons from the synchrotron. All of these systemsare preferably used in conjunction with an X-ray system capable ofcollecting X-rays of a patient in (1) a positioning system for protontreatment and (2) at a specified moment of the patient's respirationcycle. Combined, the systems provide for efficient, accurate, andprecise noninvasive tumor treatment with minimal damage to surroundinghealthy tissue.

Cyclotron/Synchrotron

A cyclotron uses a constant magnetic field and a constant-frequencyapplied electric field. One of the two fields is varied in asynchrocyclotron. Both of these fields are varied in a synchrotron.Thus, a synchrotron is a particular type of cyclic particle acceleratorin which a magnetic field is used to turn the particles so theycirculate and an electric field is used to accelerate the particles. Thesynchroton carefully synchronizes the applied fields with the travellingparticle beam.

By increasing the fields appropriately as the particles gain energy, thecharged particles path can be held constant as they are accelerated.This allows the vacuum container for the particles to be a large thintorus. In reality it is easier to use some straight sections between thebending magnets and some turning sections giving the torus the shape ofa round-cornered polygon. A path of large effective radius is thusconstructed using simple straight and curved pipe segments, unlike thedisc-shaped chamber of the cyclotron type devices. The shape also allowsand requires the use of multiple magnets to bend the particle beam.

The maximum energy that a cyclic accelerator can impart is typicallylimited by the strength of the magnetic fields and the minimumradius/maximum curvature, of the particle path. In a cyclotron themaximum radius is quite limited as the particles start at the center andspiral outward, thus this entire path must be a self-supportingdisc-shaped evacuated chamber. Since the radius is limited, the power ofthe machine becomes limited by the strength of the magnetic field. Inthe case of an ordinary electromagnet, the field strength is limited bythe saturation of the core because when all magnetic domains are alignedthe field may not be further increased to any practical extent. Thearrangement of the single pair of magnets also limits the economic sizeof the device.

Synchrotrons overcome these limitations, using a narrow beam pipesurrounded by much smaller and more tightly focusing magnets. Theability of this device to accelerate particles is limited by the factthat the particles must be charged to be accelerated at all, but chargedparticles under acceleration emit photons, thereby losing energy. Thelimiting beam energy is reached when the energy lost to the lateralacceleration required to maintain the beam path in a circle equals theenergy added each cycle. More powerful accelerators are built by usinglarge radius paths and by using more numerous and more powerfulmicrowave cavities to accelerate the particle beam between corners.Lighter particles, such as electrons, lose a larger fraction of theirenergy when turning. Practically speaking, the energy ofelectron/positron accelerators is limited by this radiation loss, whileit does not play a significant role in the dynamics of proton or ionaccelerators. The energy of those is limited strictly by the strength ofmagnets and by the cost.

Charged Particle Beam Therapy

Throughout this document, a charged particle beam therapy system, suchas a proton beam, hydrogen ion beam, or carbon ion beam, is described.Herein, the charged particle beam therapy system is described using aproton beam. However, the aspects taught and described in terms of aproton beam are not intended to be limiting to that of a proton beam andare illustrative of a charged particle beam system. Any charged particlebeam system is equally applicable to the techniques described herein.

Referring now to FIG. 1, a charged particle beam system 100 isillustrated. The charged particle beam preferably comprises a number ofsubsystems including any of: a main controller or irradiation controlmodule 110; an injection system 120; a synchrotron 130 that typicallyincludes: (1) an accelerator system 132 and (2) an extraction system134; a scanning/targeting/delivery system 140; a patient interfacemodule 150; a display system 160; and/or an imaging system 170.

An exemplary method of use of the charged particle beam system 100 isprovided. The main controller 110 controls one or more of the subsystemsto accurately and precisely deliver protons to a tumor of a patient. Forexample, the main controller 110 obtains an image, such as a portion ofa body and/or of a tumor, from the imaging system 170. The maincontroller 110 also obtains position and/or timing information from thepatient interface module 150. The main controller 110 then optionallycontrols the injection system 120 to inject a proton into a synchrotron130. The synchrotron typically contains at least an accelerator system132 and an extraction system 134. The main controller preferablycontrols the proton beam within the accelerator system, such as bycontrolling speed, trajectory, and timing of the proton beam. The maincontroller then controls extraction of a proton beam from theaccelerator through the extraction system 134. For example, thecontroller controls timing, energy, and/or intensity of the extractedbeam. The controller 110 also preferably controls targeting of theproton beam through the scanning/targeting/delivery system 140 to thepatient interface module 150. One or more components of the patientinterface module 150 are preferably controlled by the main controller110. Further, display elements of the display system 160 are preferablycontrolled via the main controller 110. Displays, such as displayscreens, are typically provided to one or more operators and/or to oneor more patients. In one embodiment, the main controller 110 times thedelivery of the proton beam from all systems, such that protons aredelivered in an optimal therapeutic manner to the patient.

Herein, the main controller 110 refers to a single system controllingthe charged particle beam system 100, to a single controller controllinga plurality of subsystems controlling the charged particle beam system100, or to a plurality of individual controllers controlling one or moresub-systems of the charged particle beam system 100.

Synchrotron

Herein, the term synchrotron is used to refer to a system maintainingthe charged particle beam in a circulating path; however, cyclotrons arealternatively used, albeit with their inherent limitations of energy,intensity, and extraction control. Further, the charged particle beam isreferred to herein as circulating along a circulating path about acentral point of the synchrotron. The circulating path is alternativelyreferred to as an orbiting path; however, the orbiting path does notrefer a perfect circle or ellipse, rather it refers to cycling of theprotons around a central point or region.

Referring now to FIG. 2, an illustrative exemplary embodiment of oneversion of the charged particle beam system 100 is provided. The number,position, and described type of components is illustrative andnon-limiting in nature. In the illustrated embodiment, an injectorsystem 210 or ion source or charged particle beam source generatesprotons. The protons are delivered into a vacuum tube that runs into,through, and out of the synchrotron. The generated protons are deliveredalong an initial path 262. Focusing magnets 230, such as quadrupolemagnets or injection quadrupole magnets, are used to focus the protonbeam path. A quadrupole magnet is a focusing magnet. An injector bendingmagnet 232 bends the proton beam toward the plane of the synchrotron130. The focused protons having an initial energy are introduced into aninjector magnet 240, which is preferably an injection Lamberson magnet.Typically, the initial beam path 262 is along an axis off of, such asabove, a circulating plane of the synchrotron 130. The injector bendingmagnet 232 and injector magnet 240 combine to move the protons into thesynchrotron 130. Main bending magnets 250 or dipole magnets orcirculating magnets are used to turn the protons along a circulatingbeam path 264. A dipole magnet is a bending magnet. The main bendingmagnets 250 bend the initial beam path 262 into a circulating beam path264. In this example, the main bending magnets 250 or circulatingmagnets are represented as four sets of four magnets to maintain thecirculating beam path 264 into a stable circulating beam path. However,any number of magnets or sets of magnets are optionally used to move theprotons around a single orbit in the circulation process. The protonspass through an accelerator 270. The accelerator accelerates the protonsin the circulating beam path 264. As the protons are accelerated, thefields applied by the magnets are increased. Particularly, the speed ofthe protons achieved by the accelerator 270 are synchronized withmagnetic fields of the main bending magnets 250 or circulating magnetsto maintain stable circulation of the protons about a central point orregion 280 of the synchrotron. At separate points in time theaccelerator 270/main bending magnet 250 combination is used toaccelerate and/or decelerate the circulating protons while maintainingthe protons in the circulating path or orbit. An extraction element ofthe inflector/deflector system 290 is used in combination with aLamberson extraction magnet 292 to remove protons from their circulatingbeam path 264 within the synchrotron 130. One example of a deflectorcomponent is a Lamberson magnet. Typically the deflector moves theprotons from the circulating plane to an axis off of the circulatingplane, such as above the circulating plane. Extracted protons arepreferably directed and/or focused using an extraction bending magnet237 and extraction focusing magnets 235, such as quadrupole magnetsalong a transport path 268 into the scanning/targeting/delivery system140. Two components of a scanning system 140 or targeting systemtypically include a first axis control 142, such as a vertical control,and a second axis control 144, such as a horizontal control. In oneembodiment, the first axis control 142 allows for about 100 mm ofvertical scanning of the proton beam 268 and the second axis control 144allows for about 700 mm of horizontal scanning of the proton beam 268. Anozzle system 146 is used for imaging the proton beam and/or as a vacuumbarrier between the low pressure beam path of the synchrotron and theatmosphere. Protons are delivered with control to the patient interfacemodule 150 and to a tumor of a patient. All of the above listed elementsare optional and may be used in various permutations and combinations.

Ion Beam Generation System

An ion beam generation system generates a negative ion beam, such as ahydrogen anion or H⁻ beam; preferably focuses the negative ion beam;converts the negative ion beam to a positive ion beam, such as a protonor H⁺ beam; and injects the positive ion beam into the synchrotron 130.Portions of the ion beam path are preferably under partial vacuum. Eachof these systems are further described, infra.

Referring now to FIG. 3, an exemplary ion beam generation system 300 isillustrated. As illustrated, the ion beam generation system 300 has fourmajor elements: a negative ion source 310, a first partial vacuum system330, an optional ion beam focusing system 350, and a tandem accelerator390.

Still referring to FIG. 3, the negative ion source 310 preferablyincludes an inlet port 312 for injection of hydrogen gas into a hightemperature plasma chamber 314. In one embodiment, the plasma chamberincludes a magnetic material 316, which provides a magnetic fieldbarrier 317 between the high temperature plasma chamber 314 and a lowtemperature plasma region on the opposite side of the magnetic fieldbarrier. An extraction pulse is applied to a negative ion extractionelectrode 318 to pull the negative ion beam into a negative ion beampath 319, which proceeds through the first partial vacuum system 330,through the ion beam focusing system 350, and into the tandemaccelerator 390.

Still referring to FIG. 3, the first partial vacuum system 330 is anenclosed system running from the hydrogen gas inlet port 312 to thetandem accelerator 390 foil 395. The foil 395 is sealed directly orindirectly to the edges of the vacuum tube 320 providing for a higherpressure, such as about 10⁻⁵ torr, to be maintained on the first partialvacuum system 330 side of the foil 395 and a lower pressure, such asabout 10⁻⁷ torr, to be maintained on the synchrotron side of the foil390. By only pumping first partial vacuum system 330 and by onlysemi-continuously operating the ion beam source vacuum based on sensorreadings, the lifetime of the semi-continuously operating pump isextended. The sensor readings are further described, infra.

Still referring to FIG. 3, the first partial vacuum system 330preferably includes: a first pump 332, such as a continuously operatingpump and/or a turbo molecular pump; a large holding volume 334; and asemi-continuously operating pump 336. Preferably, a pump controller 340receives a signal from a pressure sensor 342 monitoring pressure in thelarge holding volume 334. Upon a signal representative of a sufficientpressure in the large holding volume 334, the pump controller 340instructs an actuator 345 to open a valve 346 between the large holdingvolume and the semi-continuously operating pump 336 and instructs thesemi-continuously operating pump to turn on and pump to atmosphereresidual gases out of the vacuum line 320 about the charged particlestream. In this fashion, the lifetime of the semi-continuously operatingpump is extended by only operating semi-continuously and as needed. Inone example, the semi-continuously operating pump 336 operates for a fewminutes every few hours, such as 5 minutes every 4 hours, therebyextending a pump with a lifetime of about 2,000 hours to about 96,000hours.

Further, by isolating the inlet gas from the synchrotron vacuum system,the synchrotron vacuum pumps, such as turbo molecular pumps can operateover a longer lifetime as the synchrotron vacuum pumps have fewer gasmolecules to deal with. For example, the inlet gas is primarily hydrogengas but may contain impurities, such as nitrogen and carbon dioxide. Byisolating the inlet gases in the negative ion source system 310, firstpartial vacuum system 330, ion beam focusing system 350 and negative ionbeam side of the tandem accelerator 390, the synchrotron vacuum pumpscan operate at lower pressures with longer lifetimes, which increasesthe efficiency of the synchrotron 130.

Still referring to FIG. 3, the ion beam focusing system 350 includes twoor more electrodes where one electrode of each electrode pair partiallyobstructs the ion beam path with conductive paths 372, such as aconductive mesh. In the illustrated example, three ion beam focusingsystem sections are illustrated, a two electrode ion focusing section360, a first three electrode ion focusing section 370, and a secondthree electrode ion focusing section 380. In a given electrode pair,electric field lines, running between the conductive mesh of a firstelectrode and a second electrode, provide inward forces focusing thenegative ion beam. Multiple such electrode pairs provide multiplenegative ion beam focusing regions. Preferably the two electrode ionfocusing section 360, first three electrode ion focusing section 370,and second three electrode ion focusing section 380 are placed after thenegative ion source and before the tandem accelerator and/or cover aspace of about 0.5, 1, or 2 meters along the ion beam path. Ion beamfocusing systems are further described, infra.

Still referring to FIG. 3, the tandem accelerator 390 preferablyincludes a foil 395, such as a carbon foil. The negative ions in thenegative ion beam path 319 are converted to positive ions, such asprotons, and the initial ion beam path 262 results. The foil 395 ispreferably sealed directly or indirectly to the edges of the vacuum tube320 providing for a higher pressure, such as about 10⁻⁵ torr, to bemaintained on the side of the foil 395 having the negative ion beam path319 and a lower pressure, such as about 10⁻⁷ torr, to be maintained onthe side of the foil 390 having the proton ion beam path 262. Having thefoil 395 physically separating the vacuum chamber 320 into two pressureregions allows for a system having fewer and/or smaller pumps tomaintain the lower pressure system in the synchrotron 130 as the inlethydrogen and its residuals are extracted in a separate contained andisolated space by the first partial vacuum system 330.

Referring again to FIG. 1, another exemplary method of use of thecharged particle beam system 100 is provided. The main controller 110,or one or more sub-controllers, controls one or more of the subsystemsto accurately and precisely deliver protons to a tumor of a patient. Forexample, the main controller sends a message to the patient indicatingwhen or how to breath. The main controller 110 obtains a sensor readingfrom the patient interface module, such as a temperature breath sensoror a force reading indicative of where in a breath cycle the subject is.The main controller collects an image, such as a portion of a bodyand/or of a tumor, from the imaging system 170. The main controller 110also obtains position and/or timing information from the patientinterface module 150. The main controller 110 then optionally controlsthe injection system 120 to inject hydrogen gas into a negative ion beamsource 310 and controls timing of extraction of the negative ion fromthe negative ion beam source 310. Optionally, the main controllercontrols ion beam focusing the ion beam focusing lens system 350;acceleration of the proton beam with the tandem accelerator 390; and/orinjection of the proton into the synchrotron 130. The synchrotrontypically contains at least an accelerator system 132 and an extractionsystem 134. The synchrotron preferably contains one or more of: turningmagnets, edge focusing magnets, magnetic field concentration magnets,winding and correction coils, and flat magnetic field incident surfaces,some of which contain elements under control by the main controller 110.The main controller preferably controls the proton beam within theaccelerator system, such as by controlling speed, trajectory, and/ortiming of the proton beam. The main controller then controls extractionof a proton beam from the accelerator through the extraction system 134.For example, the controller controls timing, energy, and/or intensity ofthe extracted beam. The controller 110 also preferably controlstargeting of the proton beam through the targeting/delivery system 140to the patient interface module 150. One or more components of thepatient interface module 150 are preferably controlled by the maincontroller 110, such as vertical position of the patient, rotationalposition of the patient, and patient chairpositioning/stabilization/control elements. Further, display elements ofthe display system 160 are preferably controlled via the main controller110. Displays, such as display screens, are typically provided to one ormore operators and/or to one or more patients. In one embodiment, themain controller 110 times the delivery of the proton beam from allsystems, such that protons are delivered in an optimal therapeuticmanner to the patient.

Circulating System

A synchrotron 130 preferably comprises a combination of straightsections 410 and ion beam turning sections 420. Hence, the circulatingpath of the protons is not circular in a synchrotron, but is rather apolygon with rounded corners.

In one illustrative embodiment, the synchrotron 130, which as alsoreferred to as an accelerator system, has four straight elements andfour turning sections. Examples of straight sections 410 include the:inflector 240, accelerator 270, extraction system 290, and deflector292. Along with the four straight sections are four ion beam turningsections 420, which are also referred to as magnet sections or turningsections. Turning sections are further described, infra.

Referring now to FIG. 4, an exemplary synchrotron is illustrated. Inthis example, protons delivered along the initial proton beam path 262are inflected into the circulating beam path with the inflector 240 andafter acceleration are extracted via a deflector 292 to a beam transportpath 268. In this example, the synchrotron 130 comprises four straightsections 410 and four bending or turning sections 420 where each of thefour turning sections use one or more magnets to turn the proton beamabout ninety degrees. As is further described, infra, the ability toclosely space the turning sections and efficiently turn the proton beamresults in shorter straight sections. Shorter straight sections allowsfor a synchrotron design without the use of focusing quadrupoles in thecirculating beam path of the synchrotron. The removal of the focusingquadrupoles from the circulating proton beam path results in a morecompact design. In this example, the illustrated synchrotron has about afive meter diameter versus eight meter and larger cross-sectionaldiameters for systems using a quadrupole focusing magnet in thecirculating proton beam path.

Referring now to FIG. 5, additional description of the first bending orturning section 420 is provided. Each of the turning sections preferablycomprises multiple magnets, such as about 2, 4, 6, 8, 10, or 12 magnets.In this example, four turning magnets 510, 520, 530, 540 in the firstturning section 420 are used to illustrate key principles, which are thesame regardless of the number of magnets in a turning section 420. Aturning magnet 510 is a particular type of main bending or circulatingmagnet 250.

In physics, the Lorentz force is the force on a point charge due toelectromagnetic fields. The Lorentz force is given by equation 1 interms of magnetic fields with the election field terms not included.F=q(v×B)  eq. 1

In equation 1, F is the force in newtons; B is the magnetic field inTeslas; and v is the instantaneous velocity of the particles in metersper second.

Referring now to FIG. 6, an example of a single magnet bending orturning section 510 is expanded. The turning section includes a gap 610through which protons circulate. The gap 610 is preferably a flat gap,allowing for a magnetic field across the gap 610 that is more uniform,even, and intense. A magnetic field enters the gap 610 through amagnetic field incident surface and exits the gap 610 through a magneticfield exiting surface. The gap 610 runs in a vacuum tube between twomagnet halves. The gap 610 is controlled by at least two parameters: (1)the gap 610 is kept as large as possible to minimize loss of protons and(2) the gap 610 is kept as small as possible to minimize magnet sizesand the associated size and power requirements of the magnet powersupplies. The flat nature of the gap 610 allows for a compressed andmore uniform magnetic field across the gap 610. One example of a gapdimension is to accommodate a vertical proton beam size of about 2 cmwith a horizontal beam size of about 5 to 6 cm.

As described, supra, a larger gap size requires a larger power supply.For instance, if the gap 610 size doubles in vertical size, then thepower supply requirements increase by about a factor of 4. The flatnessof the gap 610 is also important. For example, the flat nature of thegap 610 allows for an increase in energy of the extracted protons fromabout 250 to about 330 MeV. More particularly, if the gap 610 has anextremely flat surface, then the limits of a magnetic field of an ironmagnet are reachable. An exemplary precision of the flat surface of thegap 610 is a polish of less than about 5 microns and preferably with apolish of about 1 to 3 microns. Unevenness in the surface results inimperfections in the applied magnetic field. The polished flat surfacespreads unevenness of the applied magnetic field.

Still referring to FIG. 6, the charged particle beam moves through thegap 610 with an instantaneous velocity, v. A first magnetic coil 620 anda second magnetic coil 630 run above and below the gap 610,respectively. Current running through the coils 620, 630 results in amagnetic field, B, running through the single magnet turning section510. In this example, the magnetic field, B, runs upward, which resultsin a force, F, pushing the charged particle beam inward toward a centralpoint of the synchrotron, which turns the charged particle beam in anarc.

Still referring to FIG. 6, a portion of an optional second magnetbending or turning section 520 is illustrated. The coils 620, 630typically have return elements 640, 650 or turns at the end of onemagnet, such as at the end of the first magnet turning section 510. Theturns 640, 650 take space. The space reduces the percentage of the pathabout one orbit of the synchrotron that is covered by the turningmagnets. This leads to portions of the circulating path where theprotons are not turned and/or focused and allows for portions of thecirculating path where the proton path defocuses. Thus, the spaceresults in a larger synchrotron. Therefore, the space between magnetturning sections 660 is preferably minimized. The second turning magnetis used to illustrate that the coils 620, 630 optionally run along aplurality of magnets, such as 2, 3, 4, 5, 6, or more magnets. Coils 620,630 running across multiple turning section magnets allows for twoturning section magnets to be spatially positioned closer to each otherdue to the removal of the steric constraint of the turns, which reducesand/or minimizes the space 660 between two turning section magnets.

Referring now to FIGS. 7 and 8, two illustrative 90 degree rotatedcross-sections of single magnet bending or turning sections 510 arepresented. Referring now to FIG. 8, the magnet assembly has a firstmagnet 810 and a second magnet 820. A magnetic field induced by coils,described infra, runs between the first magnet 810 to the second magnet820 across the gap 610. Return magnetic fields run through a first yoke812 and second yoke 822. The combined cross-section area of the returnyokes roughly approximates the cross-sectional area of the first magnet810 or second magnet 820. The charged particles run through the vacuumtube in the gap 610. As illustrated, protons run into FIG. 8 through thegap 610 and the magnetic field, illustrated as vector B, applies a forceF to the protons pushing the protons towards the center of thesynchrotron, which is off page to the right in FIG. 8. The magneticfield is created using windings. A first coil makes up a first windingcoil 850 and a second coil of wire makes up a second winding coil 860.Isolating or concentrating gaps 830, 840, such as air gaps, isolate theiron based yokes from the gap 610. The gap 610 is approximately flat toyield a uniform magnetic field across the gap 610, as described supra.

Still again to FIG. 7, the ends of a single bending or turning magnetare preferably beveled. Nearly perpendicular or right angle edges of aturning magnet 510 are represented by dashed lines 774, 784. The dashedlines 774, 784 intersect at a point 790 beyond the center of thesynchrotron 280.

Preferably, the edge of the turning magnet is beveled at angles alpha,α, and beta, β, which are angles formed by a first line 772, 782 goingfrom an edge of the turning magnet 510 and the center 280 and a secondline 774, 784 going from the same edge of the turning magnet and theintersecting point 790. The angle alpha is used to describe the effectand the description of angle alpha applies to angle beta, but anglealpha is optionally different from angle beta. The angle alpha providesan edge focusing effect. Beveling the edge of the turning magnet 510 atangle alpha focuses the proton beam.

Multiple turning magnets provide multiple magnet edges that each haveedge focusing effects in the synchrotron 130. If only one turning magnetis used, then the beam is only focused once for angle alpha or twice forangle alpha and angle beta. However, by using smaller turning magnets,more turning magnets fit into the turning sections 420 of thesynchrotron 130. For example, if four magnets are used in a turningsection 420 of the synchrotron, then for a single turning section thereare eight possible edge focusing effect surfaces, two edges per magnet.The eight focusing surfaces yield a smaller cross-sectional beam size.This allows the use of a smaller gap 610.

The use of multiple edge focusing effects in the turning magnets resultsin not only a smaller gap 610, but also the use of smaller magnets andsmaller power supplies. For a synchrotron 130 having four turningsections 420 where each turning sections has four turning magnets andeach turning magnet has two focusing edges, a total of thirty-twofocusing edges exist for each orbit of the protons in the circulatingpath of the synchrotron 130. Similarly, if 2, 6, or 8 magnets are usedin a given turning section, or if 2, 3, 5, or 6 turning sections areused, then the number of edge focusing surfaces expands or contractsaccording to equation 2.

$\begin{matrix}{{TFE} = {{NTS}*\frac{M}{NTS}*\frac{FE}{M}}} & {{eq}.\mspace{14mu} 2}\end{matrix}$where TFE is the number of total focusing edges, NTS is the number ofturning sections, M is the number of magnets, and FE is the number offocusing edges. Naturally, not all magnets are necessarily beveled andsome magnets are optionally beveled on only one edge.

The inventors have determined that multiple smaller magnets havebenefits over fewer larger magnets. For example, the use of 16 smallmagnets yields 32 focusing edges whereas the use of 4 larger magnetsyields only 8 focusing edges. The use of a synchrotron having morefocusing edges results in a circulating path of the synchrotron builtwithout the use of focusing quadrupoles magnets. All prior artsynchrotrons use quadrupoles in the circulating path of the synchrotron.Further, the use of quadrupoles in the circulating path necessitatesadditional straight sections in the circulating path of the synchrotron.Thus, the use of quadrupoles in the circulating path of a synchrotronresults in synchrotrons having larger diameters, circulating beampathlengths, and/or larger circumferences.

In various embodiments of the system described herein, the synchrotronhas any combination of:

-   -   at least 4 and preferably 6, 8, 10, or more edge focusing edges        per 90 degrees of turn of the charged particle beam in a        synchrotron having four turning sections;    -   at least about 16 and preferably about 24, 32, or more edge        focusing edges per orbit of the charged particle beam in the        synchrotron;    -   only 4 turning sections where each of the turning sections        includes at least 4 and preferably 8 edge focusing edges;    -   an equal number of straight sections and turning sections;    -   exactly 4 turning sections;    -   at least 4 edge focusing edges per turning section;    -   no quadrupoles in the circulating path of the synchrotron;    -   a rounded corner rectangular polygon configuration;    -   a circumference of less than 60 meters;    -   a circumference of less than 60 meters and 32 edge focusing        surfaces; and/or    -   any of about 8, 16, 24, or 32 non-quadrupole magnets per        circulating path of the synchrotron, where the non-quadrupole        magnets include edge focusing edges.

Referring again to FIG. 8, the incident magnetic field surface 870 ofthe first magnet 810 is further described. FIG. 8 is not to scale and isillustrative in nature. Local imperfections or unevenness in quality ofthe finish of the incident surface 870 results in inhomogeneities orimperfections in the magnetic field applied to the gap 610. Preferably,the incident surface 870 is flat, such as to within about a zero tothree micron finish polish, or less preferably to about a ten micronfinish polish.

Referring still to FIG. 8, additional magnet elements are described. Thefirst magnet 810 preferably contains an initial cross sectional distance890 of the iron based core. The contours of the magnetic field areshaped by the magnets 810, 820 and the yokes 812, 822. The iron basedcore tapers to a second cross sectional distance 892. The magnetic fieldin the magnet preferentially stays in the iron based core as opposed tothe gaps 830, 840. As the cross-sectional distance decreases from theinitial cross sectional distance 890 to the final cross-sectionaldistance 892, the magnetic field concentrates. The change in shape ofthe magnet from the longer distance 890 to the smaller distance 892 actsas an amplifier. The concentration of the magnetic field is illustratedby representing an initial density of magnetic field vectors 894 in theinitial cross section 890 to a concentrated density of magnetic fieldvectors 896 in the final cross section 892. The concentration of themagnetic field due to the geometry of the turning magnets results infewer winding coils 850, 860 being required and also a smaller powersupply to the coils being required.

In one example, the initial cross-section distance 890 is about fifteencentimeters and the final cross-section distance 892 is about tencentimeters. Using the provided numbers, the concentration of themagnetic field is about 15/10 or 1.5 times at the incident surface 870of the gap 610, though the relationship is not linear. The taper 842 hasa slope, such as about 20, 40, or 60 degrees. The concentration of themagnetic field, such as by 1.5 times, leads to a corresponding decreasein power consumption requirements to the magnets.

Referring still to FIG. 8, the first magnet 810 preferably contains aninitial cross sectional distance 890 of the iron based core. Thecontours of the magnetic field are shaped by the magnets 810, 820 andthe yokes 812, 822. In this example, the core tapers to a second crosssectional distance 892 with a smaller angle theta, θ. As described,supra, the magnetic field in the magnet preferentially stays in the ironbased core as opposed to the gaps 830, 840. As the cross-sectionaldistance decreases from the initial cross sectional distance 890 to thefinal cross-sectional distance 892, the magnetic field concentrates. Thesmaller angle, theta, results in a greater amplification of the magneticfield in going from the longer distance 890 to the smaller distance 892.The concentration of the magnetic field is illustrated by representingan initial density of magnetic field vectors 894 in the initial crosssection 890 to a concentrated density of magnetic field vectors 896 inthe final cross section 892. The concentration of the magnetic field dueto the geometry of the turning magnets results in fewer winding coils850, 860 being required and also a smaller power supply to the windingcoils 850, 860 being required.

Still referring to FIG. 8, optional correction coils 852, 862 areillustrated that are used to correct the strength of one or more turningmagnets. The correction coils 852, 862 supplement the winding coils 850,860. The correction coils 852, 862 have correction coil power suppliesthat are separate from winding coil power supplies used with the windingcoils 850, 860. The correction coil power supplies typically operate ata fraction of the power required compared to the winding coil powersupplies, such as about 1, 2, 3, 5, 7, or 10 percent of the power andmore preferably about 1 or 2 percent of the power used with the windingcoils 850, 860. The smaller operating power applied to the correctioncoils 852, 862 allows for more accurate and/or precise control of thecorrection coils. Correction coils are used to adjust for imperfectionin the turning magnets 510, 520, 530, 540. Optionally, separatecorrection coils are used for each turning magnet allowing individualtuning of the magnetic field for each turning magnet, which easesquality requirements in the manufacture of each turning magnet.

Referring now to FIG. 9, an example of winding coils and correctioncoils about a plurality of turning magnets 510, 520, 530, 540 in an ionbeam turning section 420 is illustrated. One or more high precisionmagnetic field sensors are placed into the synchrotron and are used tomeasure the magnetic field at or near the proton beam path. For example,the magnetic sensors 950 are optionally placed between turning magnetsand/or within a turning magnet, such as at or near the gap 610 or at ornear the magnet core or yoke. The sensors are part of a feedback systemto the correction coils. Thus, the system preferably stabilizes themagnetic field in the synchrotron elements rather that stabilizing thecurrent applied to the magnets. Stabilization of the magnetic fieldallows the synchrotron to come to a new energy level quickly. Thisallows the system to be controlled to an operator or algorithm selectedenergy level with each pulse of the synchrotron and/or with each breathof the patient.

The winding and/or correction coils correct 1, 2, 3, or 4 turningmagnets, and preferably correct a magnetic field generated by twoturning magnets. A winding or correction coil covering multiple magnetsreduces space between magnets as fewer winding or correction coil endsare required, which occupy space.

Referring now to FIG. 10A and FIG. 10B, the accelerator system 270, suchas a radio-frequency (RF) accelerator system, is further described. Theaccelerator includes a series of coils 1010-1019, such as iron orferrite coils, each circumferentially enclosing the vacuum system 320through which the proton beam 264 passes in the synchrotron 130.Referring now to FIG. 10B, the first coil 1010 is further described. Aloop of standard wire 1030 completes at least one turn about the firstcoil 1010. The loop attaches to a microcircuit 1020. Referring again toFIG. 10A, an RF synthesizer 1040, which is preferably connected to themain controller 110, provides a low voltage RF signal that issynchronized to the period of circulation of protons in the proton beampath 264. The RF synthesizer 1040, microcircuit 1020, loop 1030, andcoil 1010 combine to provide an accelerating voltage to the protons inthe proton beam path 264. For example, the RF synthesizer 1040 sends asignal to the microcircuit 1020, which amplifies the low voltage RFsignal and yields an acceleration voltage, such as about 10 volts. Theactual acceleration voltage for a single microcircuit/loop/coilcombination is about 5, 10, 15, or 20 volts, but is preferably about 10volts. Preferably, the RF-amplifier microcircuit and accelerating coilare integrated.

Still referring to FIG. 10A, the integrated RF-amplifier microcircuitand accelerating coil presented in FIG. 10B is repeated, as illustratedas the set of coils 1011-1019 surrounding the vacuum tube 320. Forexample, the RF-synthesizer 1040, under main controller 130 direction,sends an RF-signal to the microcircuits 1020-1029 connected to coils1010-1019, respectively. Each of the microcircuit/loop/coil combinationsgenerates a proton accelerating voltage, such as about 10 volts each.Hence, a set of five coil combinations generates about 50 volts forproton acceleration. Preferably about 5 to 20 microcircuit/loop/coilcombinations are used and more preferably about 9 or 10microcircuit/loop/coil combinations are used in the accelerator system270.

As a further clarifying example, the RF synthesizer 1040 sends anRF-signal, with a period equal to a period of circulation of a protonabout the synchrotron 130, to a set of ten microcircuit/loop/coilcombinations, which results in about 100 volts for acceleration of theprotons in the proton beam path 264. The 100 volts is generated at arange of frequencies, such as at about 1 MHz for a low energy protonbeam, to about 15 MHz for a high energy proton beam. The RF-signal isoptionally set at an integer multiple of a period of circulation of theproton about the synchrotron circulating path. Each of themicrocircuit/loop/coil combinations are optionally independentlycontrolled in terms of acceleration voltage and frequency.

Integration of the RF-amplifier microcircuit and accelerating coil, ineach microcircuit/loop/coil combination, results in three considerableadvantages. First, for synchrotrons, the prior art does not usemicrocircuits integrated with the accelerating coils but rather uses aset of long cables to provide power to a corresponding set of coils. Thelong cables have an impedance/resistance, which is problematic for highfrequency RF control. As a result, the prior art system is not operableat high frequencies, such as above about 10 MHz. The integratedRF-amplifier microcircuit/accelerating coil system is operable at aboveabout 10 MHz and even 15 MHz where the impedance and/or resistance ofthe long cables in the prior art systems results in poor control orfailure in proton acceleration. Second, the long cable system, operatingat lower frequencies, costs about $50,000 and the integratedmicrocircuit system costs about $1000, which is 50 times less expensive.Third, the microcircuit/loop/coil combinations in conjunction with theRF-amplifier system results in a compact low power consumption designallowing production and use of a proton cancer therapy system is a smallspace, as described supra, and in a cost effective manner.

Referring now to FIG. 11, an example is used to clarify the magneticfield control using a feedback loop 1100 to change delivery times and/orperiods of proton pulse delivery. In one case, a respiratory sensor 1110senses the breathing cycle of the subject. The respiratory sensor sendsthe information to an algorithm in a magnetic field controller 1120,typically via the patient interface module 150 and/or via the maincontroller 110 or a subcomponent thereof. The algorithm predicts and/ormeasures when the subject is at a particular point in the breathingcycle, such as at the bottom of a breath. Magnetic field sensors 1130are used as input to the magnetic field controller, which controls amagnet power supply 1140 for a given magnetic field 1150, such as withina first turning magnet 510 of a synchrotron 130. The control feedbackloop is thus used to dial the synchrotron to a selected energy level anddeliver protons with the desired energy at a selected point in time,such as at the bottom of the breath. More particularly, the maincontroller injects protons into the synchrotron and accelerates theprotons in a manner that combined with extraction delivers the protonsto the tumor at a selected point in the breathing cycle. Intensity ofthe proton beam is also selectable and controllable by the maincontroller at this stage. The feedback control to the correction coilsallows rapid selection of energy levels of the synchrotron that are tiedto the patient's breathing cycle. This system is in stark contrast to asystem where the current is stabilized and the synchrotron deliverpulses with a period, such as 10 or 20 cycles per second with a fixedperiod. Optionally, the feedback or the magnetic field design coupledwith the correction coils allows for the extraction cycle to match thevarying respiratory rate of the patient.

Traditional extraction systems do not allow this control as magnets havememories in terms of both magnitude and amplitude of a sine wave. Hence,in a traditional system, in order to change frequency, slow changes incurrent must be used. However, with the use of the feedback loop usingthe magnetic field sensors, the frequency and energy level of thesynchrotron are rapidly adjustable. Further aiding this process is theuse of a novel extraction system that allows for acceleration of theprotons during the extraction process, described infra.

EXAMPLE III

Referring again to FIG. 9, an example of a winding coil 930 that coverstwo turning magnets 510, 520 is provided. Optionally, a first windingcoil 940 covers one magnets or a second winding coil 920 covers aplurality of magnets 510, 520. As described, supra, this system reducesspace between turning section allowing more magnetic field to be appliedper radian of turn. A first correction coil 910 is illustrated that isused to correct the magnetic field for the first turning magnet 510. Asecond correction coil 920 is illustrated that is used to correct themagnetic field for a winding coil 930 about two turning magnets.Individual correction coils for each turning magnet are preferred andindividual correction coils yield the most precise and/or accuratemagnetic field in each turning section. Particularly, the individualcorrection coil 910 is used to compensate for imperfections in theindividual magnet of a given turning section. Hence, with a series ofmagnetic field sensors, corresponding magnetic fields are individuallyadjustable in a series of feedback loops, via a magnetic fieldmonitoring system, as an independent coil is used for each turningsection. Alternatively, a multiple magnet correction coil is used tocorrect the magnetic field for a plurality of turning section magnets.

Flat Gap Surface

While the gap surface is described in terms of the first turning magnet510, the discussion applies to each of the turning magnets in thesynchrotron. Similarly, while the gap 610 surface is described in termsof the magnetic field incident surface 670, the discussion additionallyoptionally applies to the magnetic field exiting surface 680.

The magnetic field incident surface 870 of the first magnet 810 ispreferably about flat, such as to within about a zero to three micronfinish polish or less preferably to about a ten micron finish polish. Bybeing very flat, the polished surface spreads the unevenness of theapplied magnetic field across the gap 610. The very flat surface, suchas about 0, 1, 2, 4, 6, 8, 10, 15, or 20 micron finish, allows for asmaller gap size, a smaller applied magnetic field, smaller powersupplies, and tighter control of the proton beam cross-sectional area.The magnetic field exiting surface 880 is also preferably flat.

Proton Beam Extraction

Referring now to FIG. 12, an exemplary proton extraction process fromthe synchrotron 130 is illustrated. For clarity, FIG. 12 removeselements represented in FIG. 2, such as the turning magnets, whichallows for greater clarity of presentation of the proton beam path as afunction of time. Generally, protons are extracted from the synchrotron130 by slowing the protons. As described, supra, the protons wereinitially accelerated in a circulating path 264, which is maintainedwith a plurality of main bending magnets 250. The circulating path isreferred to herein as an original central beamline 264. The protonsrepeatedly cycle around a central point in the synchrotron 280. Theproton path traverses through a radio frequency (RF) cavity system 1210.To initiate extraction, an RF field is applied across a first blade 1212and a second blade 1214, in the RF cavity system 1210. The first blade1212 and second blade 1214 are referred to herein as a first pair ofblades.

In the proton extraction process; an RF voltage is applied across thefirst pair of blades, where the first blade 1212 of the first pair ofblades is on one side of the circulating proton beam path 264 and thesecond blade 1214 of the first pair of blades is on an opposite side ofthe circulating proton beam path 264. The applied RF field appliesenergy to the circulating charged-particle beam. The applied RF fieldalters the orbiting or circulating beam path slightly of the protonsfrom the original central beamline 264 to an altered circulating beampath 265. Upon a second pass of the protons through the RF cavitysystem, the RF field further moves the protons off of the originalproton beamline 264. For example, if the original beamline is consideredas a circular path, then the altered beamline is slightly elliptical.The applied RF field is timed to apply outward or inward movement to agiven band of protons circulating in the synchrotron accelerator. Eachorbit of the protons is slightly more off axis compared to the originalcirculating beam path 264. Successive passes of the protons through theRF cavity system are forced further and further from the originalcentral beamline 264 by altering the direction and/or intensity of theRF field with each successive pass of the proton beam through the RFfield.

The RF voltage is frequency modulated at a frequency about equal to theperiod of one proton cycling around the synchrotron for one revolutionor at a frequency than is an integral multiplier of the period of oneproton cycling about the synchrotron. The applied RF frequency modulatedvoltage excites a betatron oscillation. For example, the oscillation isa sine wave motion of the protons.

The process of timing the RF field to a given proton beam within the RFcavity system is repeated thousands of times with each successive passof the protons being moved approximately one micrometer further off ofthe original central beamline 264. For clarity, the approximately 1000changing beam paths with each successive path of a given band of protonsthrough the RF field are illustrated as the altered beam path 265.

With a sufficient sine wave betatron amplitude, the altered circulatingbeam path 265 touches a material 1230, such as a foil or a sheet offoil. The foil is preferably a lightweight material, such as beryllium,a lithium hydride, a carbon sheet, or a material of low nuclear charge.A material of low nuclear charge is a material composed of atomsconsisting essentially of atoms having six or fewer protons. The foil ispreferably about 10 to 150 microns thick, is more preferably 30 to 100microns thick, and is still more preferably 40-60 microns thick. In oneexample, the foil is beryllium with a thickness of about 50 microns.When the protons traverse through the foil, energy of the protons islost and the speed of the protons is reduced. Typically, a current isalso generated, described infra. Protons moving at a slower speed travelin the synchrotron with a reduced radius of curvature 266 compared toeither the original central beamline 264 or the altered circulating path265. The reduced radius of curvature 266 path is also referred to hereinas a path having a smaller diameter of trajectory or a path havingprotons with reduced energy. The reduced radius of curvature 266 istypically about two millimeters less than a radius of curvature of thelast pass of the protons along the altered proton beam path 265.

The thickness of the material 1230 is optionally adjusted to created achange in the radius of curvature, such as about ½, 1, 2, 3, or 4 mmless than the last pass of the protons 265 or original radius ofcurvature 264. Protons moving with the smaller radius of curvaturetravel between a second pair of blades. In one case, the second pair ofblades is physically distinct and/or are separated from the first pairof blades. In a second case, one of the first pair of blades is also amember of the second pair of blades. For example, the second pair ofblades is the second blade 1214 and a third blade 1216 in the RF cavitysystem 1210. A high voltage DC signal, such as about 1 to 5 kV, is thenapplied across the second pair of blades, which directs the protons outof the synchrotron through an extraction magnet 292, such as a Lambersonextraction magnet, into a transport path 268.

Control of acceleration of the charged particle beam path in thesynchrotron with the accelerator and/or applied fields of the turningmagnets in combination with the above described extraction system allowsfor control of the intensity of the extracted proton beam, whereintensity is a proton flux per unit time or the number of protonsextracted as a function of time. For example, when a current is measuredbeyond a threshold, the RF field modulation in the RF cavity system isterminated or reinitiated to establish a subsequent cycle of proton beamextraction. This process is repeated to yield many cycles of proton beamextraction from the synchrotron accelerator.

Because the extraction system does not depend on any change in magneticfield properties, it allows the synchrotron to continue to operate inacceleration or deceleration mode during the extraction process. Stateddifferently, the extraction process does not interfere with synchrotronacceleration. In stark contrast, traditional extraction systemsintroduce a new magnetic field, such as via a hexapole, during theextraction process. More particularly, traditional synchrotrons have amagnet, such as a hexapole magnet, that is off during an accelerationstage. During the extraction phase, the hexapole magnetic field isintroduced to the circulating path of the synchrotron. The introductionof the magnetic field necessitates two distinct modes, an accelerationmode and an extraction mode, which are mutually exclusive in time.

Charged Particle Beam Intensity Control

Control of applied field, such as a radio-frequency (RF) field,frequency and magnitude in the RF cavity system 1210 allows forintensity control of the extracted proton beam, where intensity isextracted proton flux per unit time or the number of protons extractedas a function of time.

Referring still to FIG. 12, when protons in the proton beam hit thematerial 1230 electrons are given off resulting in a current. Theresulting current is converted to a voltage and is used as part of a ionbeam intensity monitoring system or as part of an ion beam feedback loopfor controlling beam intensity. The voltage is optionally measured andsent to the main controller 110 or to a controller subsystem. Moreparticularly, when protons in the charged particle beam path passthrough the material 1230, some of the protons lose a small fraction oftheir energy, such as about one-tenth of a percent, which results in asecondary electron. That is, protons in the charged particle beam pushsome electrons when passing through material 1230 giving the electronsenough energy to cause secondary emission. The resulting electron flowresults in a current or signal that is proportional to the number ofprotons going through the target material 1230. The resulting current ispreferably converted to voltage and amplified. The resulting signal isreferred to as a measured intensity signal.

The amplified signal or measured intensity signal resulting from theprotons passing through the material 1230 is preferably used incontrolling the intensity of the extracted protons. For example, themeasured intensity signal is compared to a goal signal, which ispredetermined in an irradiation of the tumor plan 1260. In one example,the tumor plan 1260 contains the goal or targeted energy and intensityof the delivered proton beam as a function of x-position, y-position,time, and/or rotational position of the patient. The difference betweenthe measured intensity signal and the planned for goal signal iscalculated. The difference is used as a control to the RF generator.Hence, the measured flow of current resulting from the protons passingthrough the material 1230 is used as a control in the RF generator toincrease or decrease the number of protons undergoing betatronoscillation and striking the material 1230. Hence, the voltagedetermined off of the material 1230 is used as a measure of the orbitalpath and is used as a feedback control to control the RF cavity system.Alternatively, the measured intensity signal is not used in the feedbackcontrol and is just used as a monitor of the intensity of the extractedprotons.

As described, supra, the photons striking the material 1230 is a step inthe extraction of the protons from the synchrotron 130. Hence, themeasured intensity signal is used to change the number of protons perunit time being extracted, which is referred to as intensity of theproton beam. The intensity of the proton beam is thus under algorithmcontrol. Further, the intensity of the proton beam is controlledseparately from the velocity of the protons in the synchrotron 130.Hence, intensity of the protons extracted and the energy of the protonsextracted are independently variable.

For example, protons initially move at an equilibrium trajectory in thesynchrotron 130. An RF field is used to excite the protons into abetatron oscillation. In one case, the frequency of the protons orbit isabout 10 MHz. In one example, in about one millisecond or after about10,000 orbits, the first protons hit an outer edge of the targetmaterial 130. The specific frequency is dependent upon the period of theorbit. Upon hitting the material 130, the protons push electrons throughthe foil to produce a current. The current is converted to voltage andamplified to yield a measured intensity signal. The measured intensitysignal is used as a feedback input to control the applied RF magnitude,RF frequency, or RF field. Preferably, the measured intensity signal iscompared to a target signal and a measure of the difference between themeasured intensity signal and target signal is used to adjust theapplied RF field in the RF cavity system 1210 in the extraction systemto control the intensity of the protons in the extraction step. Statedagain, the signal resulting from the protons striking and/or passingthrough the material 130 is used as an input in RF field modulation. Anincrease in the magnitude of the RF modulation results in protonshitting the foil or material 130 sooner. By increasing the RF, moreprotons are pushed into the foil, which results in an increasedintensity, or more protons per unit time, of protons extracted from thesynchrotron 130.

In another example, a detector 1250 external to the synchrotron 130 isused to determine the flux of protons extracted from the synchrotron anda signal from the external detector is used to alter the RF field or RFmodulation in the RF cavity system 1210. Here the external detectorgenerates an external signal, which is used in a manner similar to themeasured intensity signal, described in the preceding paragraphs.Particularly, the measured intensity signal is compared to a desiredsignal from the irradiation plan 1260 in a feedback intensity controller1240, which adjusts the RF field between the first plate 1212 and thesecond plate 1214 in the extraction process, described supra.

In yet another example, when a current from material 130 resulting fromprotons passing through or hitting material is measured beyond athreshold, the RF field modulation in the RF cavity system is terminatedor reinitiated to establish a subsequent cycle of proton beamextraction. This process is repeated to yield many cycles of proton beamextraction from the synchrotron accelerator.

In still yet another embodiment, intensity modulation of the extractedproton beam is controlled by the main controller 110. The maincontroller 110 optionally and/or additionally controls timing ofextraction of the charged particle beam and energy of the extractedproton beam.

The benefits of the system include a multi-dimensional scanning system.Particularly, the system allows independence in: (1) energy of theprotons extracted and (2) intensity of the protons extracted. That is,energy of the protons extracted is controlled by an energy controlsystem and an intensity control system controls the intensity of theextracted protons. The energy control system and intensity controlsystem are optionally independently controlled. Preferably, the maincontroller 110 controls the energy control system and the maincontroller simultaneously controls the intensity control system to yieldan extracted proton beam with controlled energy and controlled intensitywhere the controlled energy and controlled intensity are independentlyvariable. Thus the irradiation spot hitting the tumor is underindependent control of:

-   -   time;    -   energy;    -   intensity;    -   x-axis position, where the x-axis represents horizontal movement        of the proton beam relative to the patient, and    -   y-axis position, where the y-axis represents vertical movement        of the proton beam relative to the patient.

In addition, the patient is optionally independently rotated relative toa translational axis of the proton beam at the same time. The system iscapable of pulse-to-pulse energy variability. Additionally, the systemis capable of dynamic energy modulation during a pulse, enabling truethree-dimensional proton beam scanning with energy and/or intensitymodulation.

Referring now to FIG. 13, a proton beam position verification system1300 is described. A nozzle 1310 provides an outlet for the secondreduced pressure vacuum system initiating at the foil 395 of the tandemaccelerator 390 and running through the synchrotron 130 to a nozzle foil1320 covering the end of the nozzle 1310. The nozzle expands incross-sectional area along the z-axis of the proton beam path 268 toallow the proton beam 268 to be scanned along the x- and y-axes by thevertical control element 142 and horizontal control element 144,respectively. The nozzle foil 1320 is preferably mechanically supportedby the outer edges of an exit port of the nozzle 1310. An example of anozzle foil 1320 is a sheet of about 0.1 inch thick aluminum foil.Generally, the nozzle foil separates atmosphere pressures on the patientside of the nozzle foil 1320 from the low pressure region, such as about10⁻⁵ to 10⁻⁷ torr region, on the synchrotron 130 side of the nozzle foil1320. The low pressure region is maintained to reduce scattering of theproton beam 264, 268.

Still referring to FIG. 13, the proton beam verification system 1300 isa system that allows for monitoring of the actual proton beam position268, 269 in real-time without destruction of the proton beam. The protonbeam verification system 1300 preferably includes a proton beam positionverification layer 1330, which is also referred to herein as a coating,luminescent, fluorescent, phosphorescent, radiance, or viewing layer.The verification layer or coating layer 1330 is preferably a coating orthin layer substantially in contact with an inside surface of the nozzlefoil 1320, where the inside surface is on the synchrotron side of thenozzle foil 1320. Less preferably, the verification layer or coatinglayer 1330 is substantially in contact with an outer surface of thenozzle foil 1320, where the outer surface is on the patient treatmentside of the nozzle foil 1320. Preferably, the nozzle foil 1320 providesa substrate surface for coating by the coating layer, but optionally aseparate coating layer support element, on which the coating 1330 ismounted, is placed anywhere in the proton beam path 268.

Still referring to FIG. 13, the coating 1330 yields a measurablespectroscopic response, spatially viewable by the detector 1340, as aresult of transmission by the proton beam 268. The coating 1330 ispreferably a phosphor, but is optionally any material that is viewableor imaged by a detector where the material changes spectroscopically asa result of the proton beam path 268 hitting or transmitting through thecoating 1330. A detector or camera 1340 views the coating layer 1330 anddetermines the current position of the proton beam 268 by thespectroscopic differences resulting from protons passing through thecoating layer. For example, the camera 1340 views the coating surface1330 as the proton beam 268 is being scanned by the horizontal 144 andvertical 142 beam position control elements during treatment of thetumor 1420. The camera 1340 views the current position of the protonbeam 268 as measured by spectroscopic response. The coating layer 1330is preferably a phosphor or luminescent material that glows or emitsphotons for a short period of time, such as less than 5 seconds for a50% intensity, as a result of excitation by the proton beam 268.Optionally, a plurality of cameras or detectors 1340 are used, whereeach detector views all or a portion of the coating layer 1330. Forexample, two detectors 1340 are used where a first detector views afirst half of the coating layer and the second detector views a secondhalf of the coating layer. Preferably, the detector 1340 is mounted intothe nozzle 1310 to view the proton beam position after passing throughthe first axis and second axis controllers 142, 144. Preferably, thecoating layer 1330 is positioned in the proton beam path 268 in aposition prior to the protons striking the patient 1430.

Still referring to FIG. 13, the main controller 130, connected to thecamera or detector 1340 output, compares the actual proton beam position268 with the planned proton beam position and/or a calibration referenceto determine if the actual proton beam position 268 is within tolerance.The proton beam verification system 1300 preferably is used in at leasttwo phases, a calibration phase and a proton beam treatment phase. Thecalibration phase is used to correlate, as a function of x-, y-positionof the glowing response the actual x-, y-position of the proton beam atthe patient interface. During the proton beam treatment phase, theproton beam position is monitored and compared to the calibration and/ortreatment plan to verify accurate proton delivery to the tumor 1420and/or as a proton beam shutoff safety indicator.

Patient Positioning

Referring now to FIG. 14, the patient is preferably positioned on orwithin a patient positioning system 1410 of the patient interface module150. The patient positioning system 1410 is used to translate thepatient and/or rotate the patient into a zone where the proton beam canscan the tumor using a scanning system 140 or proton targeting system,described infra. Essentially, the patient positioning system 1410performs large movements of the patient to place the tumor near thecenter of a proton beam path 268 and the proton scanning or targetingsystem 140 performs fine movements of the momentary beam position 269 intargeting the tumor 1420. To illustrate, FIG. 14 shows the momentaryproton beam position 269 and a range of scannable positions 1440 usingthe proton scanning or targeting system 140, where the scannablepositions 1440 are about the tumor 1420 of the patient 1430. In thisexample, the scannable positions are scanned along the x- and y-axes;however, scanning is optionally simultaneously performed along thez-axis as described infra. This illustratively shows that the y-axismovement of the patient occurs on a scale of the body, such asadjustment of about 1, 2, 3, or 4 feet, while the scannable region ofthe proton beam 268 covers a portion of the body, such as a region ofabout 1, 2, 4, 6, 8, 10, or 12 inches. The patient positioning systemand its rotation and/or translation of the patient combines with theproton targeting system to yield precise and/or accurate delivery of theprotons to the tumor.

Referring still to FIG. 14, the patient positioning system 1410optionally includes a bottom unit 1412 and a top unit 1414, such asdiscs or a platform. Referring now to FIG. 14A, the patient positioningunit 1410 is preferably y-axis adjustable 1416 to allow verticalshifting of the patient relative to the proton therapy beam 268.Preferably, the vertical motion of the patient positioning unit 1410 isabout 10, 20, 30, or 50 centimeters per minute. Referring now to FIG.14B, the patient positioning unit 1410 is also preferably rotatable 1417about a rotation axis, such as about the y-axis running through thecenter of the bottom unit 1412 or about a y-axis running through thetumor 1420, to allow rotational control and positioning of the patientrelative to the proton beam path 268. Preferably the rotational motionof the patient positioning unit 1410 is about 360 degrees per minute.Optionally, the patient positioning unit rotates about 45, 90, or 180degrees. Optionally, the patient positioning unit 1410 rotates at a rateof about 45, 90, 180, 360, 720, or 1080 degrees per minute. The rotationof the positioning unit 1417 is illustrated about the rotation axis attwo distinct times, t₁ and t₂. Protons are optionally delivered to thetumor 1420 at n times where each of the n times represent differentdirections of the incident proton beam 269 hitting the patient 1430 dueto rotation of the patient 1417 about the rotation axis.

Any of the semi-vertical, sitting, or laying patient positioningembodiments described, infra, are optionally vertically translatablealong the y-axis or rotatable about the rotation or y-axis.

Preferably, the top and bottom units 1412, 1414 move together, such thatthey rotate at the same rates and translate in position at the samerates. Optionally, the top and bottom units 1412, 1414 are independentlyadjustable along the y-axis to allow a difference in distance betweenthe top and bottom units 1412, 1414. Motors, power supplies, andmechanical assemblies for moving the top and bottom units 1412, 1414 arepreferably located out of the proton beam path 269, such as below thebottom unit 1412 and/or above the top unit 1414. This is preferable asthe patient positioning unit 1410 is preferably rotatable about 360degrees and the motors, power supplies, and mechanical assembliesinterfere with the protons if positioned in the proton beam path 269.

Proton Delivery Efficiency

Referring now to FIG. 15, a common distribution of relative doses forboth X-rays and proton irradiation is presented. As shown, X-raysdeposit their highest dose near the surface of the targeted tissue andthen exponentially decreases as a function of tissue depth. Thedeposition of X-ray energy near the surface is non-ideal for tumorslocated deep within the body, which is usually the case, as excessivedamage is done to the soft tissue layers surrounding the tumor 1420.

The advantage of protons is that they deposit most of their energy nearthe end of the flight trajectory as the energy loss per unit path of theabsorber transversed by a proton increases with decreasing particlevelocity, giving rise to a sharp maximum in ionization near the end ofthe range, referred to herein as the Bragg peak. Furthermore, since theflight trajectory of the protons is variable by increasing or decreasingtheir initial kinetic energy or initial velocity, then the peakcorresponding to maximum energy is movable within the tissue. Thusz-axis control of the proton depth of penetration is allowed by theacceleration/extraction process, described supra. As a result of theprotons dose-distribution characteristics, a radiation oncologist canoptimize dosage to the tumor 1420 while minimizing dosage to surroundingnormal tissues.

The Bragg peak energy profile shows that protons deliver their energyacross the entire length of the body penetrated by the proton up to amaximum penetration depth. As a result, energy is being delivered, inthe ingress portion of the Bragg peak energy profile, to healthy tissue,bone, and other body constituents before the proton beam hits the distalor back side of the tumor. It follows that the shorter the pathlength inthe body prior to the tumor, the higher the efficiency of protondelivery efficiency, where proton delivery efficiency is a measure ofhow much energy is delivered to the tumor relative to healthy portionsof the patient. Examples of proton delivery efficiency include: (1) aratio of proton energy delivered to the tumor over proton energydelivered to non-tumor tissue; (2) pathlength of protons in the tumorversus pathlength in the non-tumor tissue; and (3) damage to a tumorcompared to damage to healthy body parts. Any of these measures areoptionally weighted by damage to sensitive tissue, such as a nervoussystem element, heart, brain, or other organ. To illustrate, for apatient in a laying position where the patient is rotated about they-axis during treatment, a tumor near the heart would at times betreated with protons running through the head-to-heart path,leg-to-heart path, or hip-to-heart path, which are all inefficientcompared to a patient in a sitting or semi-vertical position where theprotons are all delivered through a shorter chest-to-heart;side-of-body-to-heart, or back-to-heart path. Particularly, compared toa laying position, using a sitting or semi-vertical position of thepatient, a shorter pathlength through the body to a tumor is provided toa tumor located in the torso or head, which results in a higher orbetter proton delivery efficiency.

Herein proton delivery efficiency is separately described from the timeefficiency or synchrotron use efficiency, which is a fraction of timethat the charged particle beam apparatus is in operation.

Depth Targeting

Referring now to FIGS. 16 A-E, x-axis scanning of the proton beam isillustrated while z-axis energy of the proton beam undergoes controlledvariation 1600 to allow irradiation of slices of the tumor 1420. Forclarity of presentation, the simultaneous y-axis scanning that isperformed is not illustrated. In FIG. 16A, irradiation is commencingwith the momentary proton beam position 269 at the start of a firstslice. Referring now to FIG. 16B, the momentary proton beam position isat the end of the first slice. Importantly, during a given slice ofirradiation, the proton beam energy is preferably continuouslycontrolled and changed according to the tissue density in front of thetumor 1420. The variation of the proton beam energy to account fortissue density thus allows the beam stopping point, or Bragg peak, toremain inside the tissue slice. The variation of the proton beam energyduring scanning is possible due to the acceleration/extractiontechniques, described supra, which allow for acceleration of the protonbeam during extraction. FIGS. 16C, 16D, and 16E show the momentaryproton beam position in the middle of the second slice, two-thirds ofthe way through a third slice, and after finalizing irradiation from agiven direction, respectively. Using this approach, controlled,accurate, and precise delivery of proton irradiation energy to the tumor1420, to a designated tumor subsection, or to a tumor layer is achieved.Efficiency of deposition of proton energy to tumor, as defined as theratio of the proton irradiation energy delivered to the tumor relativeto the proton irradiation energy delivered to the healthy tissue isfurther described infra.

Multi-Field Irradiation

It is desirable to maximize efficiency of deposition of protons to thetumor 1420, as defined by maximizing the ratio of the proton irradiationenergy delivered to the tumor 1420 relative to the proton irradiationenergy delivered to the healthy tissue. Irradiation from one, two, orthree directions into the body, such as by rotating the body about 90degrees between irradiation sub-sessions results in proton irradiationfrom the ingress portion of the Bragg peak concentrating into one, two,or three healthy tissue volumes, respectively. It is desirable tofurther distribute the ingress portion of the Bragg peak energy evenlythrough the healthy volume tissue surrounding the tumor 1420.

Multi-field irradiation is proton beam irradiation from a plurality ofentry points into the body. For example, the patient 1430 is rotated andthe radiation source point is held constant. For example, as the patient1430 is rotated through 360 degrees and proton therapy is applied from amultitude of angles resulting in the distal radiation beingcircumferentially spread in the tumor and ingress energy beingdistributed about the tumor yielding enhanced proton irradiationefficiency. In one case, the body is rotated into greater than 3, 5, 10,15, 20, 25, 30, or 35 positions and proton irradiation occurs with eachrotation position. Rotation of the patient for proton therapy or forX-ray imaging is preferably about 45, 90, 135, 180, 270, or 360 degrees.Rotation of the patient is preferably performed using the patientpositioning system 1410 and/or the bottom unit 1412 or disc, describedsupra. Rotation of the patient 1430 while keeping the delivery protonbeam 268 in a relatively fixed orientation allows irradiation of thetumor 1420 from multiple directions without use of a new collimator foreach direction. Further, as no new setup is required for each rotationposition of the patient 1430, the system allows the tumor 1420 to betreated from multiple directions without reseating or positioning thepatient, thereby minimizing tumor 1420 regeneration time and increasingpatient 1430 cancer therapy throughput.

The patient is optionally centered on the bottom unit 1412 or the tumor1420 is optionally centered on the bottom unit 1412. If the patient iscentered on the bottom unit 1412, then the first axis control element142 and second axis control element 144 are programmed to compensate forthe off central axis of rotation position variation of the tumor 1420.

Referring now to FIGS. 17 A-E, an example of multi-field irradiation1700 is presented. In this example, five patient rotation positions areillustrated; however, the five rotation positions are discrete rotationpositions of about thirty-six rotation positions, where the body isrotated about ten degrees with each position. Referring now to FIG. 17A,a range of irradiation beam positions 269 is illustrated from a firstbody rotation position, illustrated as the patient 1430 facing theproton irradiation beam where a first healthy volume 1711 is irradiatedby the ingress portion of the Bragg peak energy irradiation profile.Referring now to FIG. 17B, the patient 1430 is rotated about fortydegrees and the irradiation is repeated. In the second position, thetumor 1420 again receives the bulk of the irradiation energy and asecond healthy tissue volume 1712 receives the smaller ingress portionof the Bragg peak energy. Referring now to FIGS. 17 C-E, the patient1430 is rotated a total of about 90, 130, and 180 degrees, respectively.For each of the third, fourth, and fifth rotation positions, the tumor1420 receives the bulk of the irradiation energy and the third 1713,fourth 1714, and fifth 1715 healthy tissue volumes receive the smalleringress portion of the Bragg peak energy, respectively. Thus, therotation of the patient during proton therapy results in the ingressenergy of the delivered proton energy to be distributed about the tumor1420, such as to regions one to five, while along a given axis, at leastabout 75, 80, 85, 90, or 95 percent of the energy is delivered to thetumor 1420.

For a given rotation position, all or part of the tumor is irradiated.For example, in one embodiment only a distal section or distal slice ofthe tumor 1420 is irradiated with each rotation position, where thedistal section is a section furthest from the entry point of the protonbeam into the patient 1430. For example, the distal section is thedorsal side of the tumor when the patient 1430 is facing the proton beamand the distal section is the ventral side of the tumor when the patient1430 is facing away from the proton beam.

Referring now to FIG. 18, a second example of multi-field irradiation1800 is presented where the proton source is stationary and the patient1430 is rotated. For ease of presentation, the proton beam path 269 isillustrated as entering the patient 1430 from varying sides at times t₁,t₂, t₃, . . . , t_(n), t_(n+1). At a first time, t₁, the low energydelivery end or ingress end of the Bragg peak profile hits a first area1810, A₁. The pahtient is rotated and the proton beam path isillustrated at a second time, t₂, where the low energy end of the Braggpeak hits a second area 1820, A₂. At a third time, the ingress area ofthe Bragg peak profile hits a third area 1830, A₃. This rotation andirradiation process is repeated n times, where n is a positive numbergreater than four and preferably greater than about 10, 20, 30, 100, or300. At an n^(th) time the ingress end of the Bragg peak profile strikesan n^(th) area 1840. As illustrated, at an n^(th) time, t_(n), if thepatient 1430 is rotated further, the proton beam would hit a sensitivebody constituent 1450, such as the spinal cord or eyes. Irradiation ispreferably suspended until the sensitive body constituent is rotated outof the proton beam path. Irradiation is resumed at a time, t_(n+1),after the sensitive body constituent 1450 is rotated our of the protonbeam path. At time t_(n+1) the Bragg peak ingress energy strikes at_(n+1) area 1450. At times 1, 2, 3, . . . n, n+1, the high energydistal region of Bragg peak profile falls within the tumor 1420. In thismanner, the Bragg peak energy is always within the tumor, the ingressregion of the Bragg peak profile is distributed in healthy tissue aboutthe tumor 1420, and sensitive body constituents 1450 receive minimal orno proton beam irradiation.

Proton Delivery Efficiency

Herein, charged particle or proton delivery efficiency is radiation dosedelivered to the tumor compared to radiation dose delivered to thehealthy regions of the patient.

A proton delivery enhancement method is described where proton deliveryefficiency is enhanced, optimized, or maximized. In general, multi-fieldirradiation is used to deliver protons to the tumor from a multitude ofrotational directions. From each direction, the energy of the protons isadjusted to target the distal portion of the tumor, where the distalportion of the tumor is the volume of the tumor furthest from the entrypoint of the proton beam into the body.

For clarity, the process is described using an example where the outeredges of the tumor are initially irradiated using distally appliedradiation through a multitude of rotational positions, such as through360 degrees. This results in a symbolic or calculated remaining smallertumor for irradiation. The process is then repeated as many times asnecessary on the smaller tumor. However, the presentation is forclarity. In actuality, irradiation from a given rotational angle isperformed once with z-axis proton beam energy and intensity beingadjusted for the calculated smaller inner tumors during x- and y-axisscanning.

Referring now to FIG. 19, the proton delivery enhancement method isfurther described. Referring now to FIG. 19A, at a first point in timeprotons are delivered to the tumor 1420 of the patient 1430 from a firstdirection. From the first rotational direction, the proton beam isscanned 269 across the tumor. As the proton beam is scanned across thetumor the energy of the proton beam is adjusted to allow the Bragg peakenergy to target the distal portion of the tumor. Again, distal refersto the back portion of the tumor located furthest away from where thecharged particles enter the tumor. As illustrated, the proton beam isscanned along an x-axis across the patient. This process allows theBragg peak energy to fall within the tumor, for the middle area of theBragg peak profile to fall in the middle and proximal portion of thetumor, and for the small intensity ingress portion of the Bragg peak tohit healthy tissue. In this manner, the maximum radiation dose isdelivered to the tumor or the proton dose efficiency is maximized forthe first rotational direction.

After irradiation from the first rotational position, the patient isrotated to a new rotational position. Referring now to FIG. 19B, thescanning of the proton beam is repeated. Again, the distal portion ofthe tumor is targeted with adjustment of the proton beam energy totarget the Bragg peak energy to the distal portion of the tumor.Naturally, the distal portion of the tumor for the second rotationalposition is different from the distal portion of the tumor for the firstrotational position. Referring now to FIG. 19C, the process of rotatingthe patient and then irradiating the new distal portion of the tumor isfurther illustrated at an n^(th) rotational position. Preferably, theprocess of rotating the patient and scanning along the x- and y-axeswith the Z-axes energy targeting the new distal portion of the tumor isrepeated, such as with more than 5, 10, 20, or 30 rotational positionsor with about 36 rotational positions.

For clarity, FIGS. 19A-C and FIG. 19E show the proton beam as havingmoved, but in actuality, the proton beam is stationary and the patientis rotated, such as via use of rotating the bottom unit 1412 of thepatient positioning system 1410. Also, FIGS. 19A-C and FIG. 19E show theproton beam being scanned across the tumor along the x-axis. Though notillustrated for clarity, the proton beam is additionally scanned up anddown the tumor along the y-axis of the patient. Combined, the distalportion or volume of the tumor is irradiated along the x- and y-axeswith adjustment of the z-axis energy level of the proton beam. In onecase, the tumor is scanned along the x-axis and the scanning is repeatedalong the x-axis for multiple y-axis positions. In another case, thetumor is scanned along the y-axis and the scanning is repeated along they-axis for multiple x-axis positions. In yet another case, the tumor isscanned by simultaneously adjusting the x- and y-axes so that the distalportion of the tumor is targeted. In all of these cases, the z-axis orenergy of the proton beam is adjusted along the contour of the distalportion of the tumor to target the Bragg peak energy to the distalportion of the tumor.

Referring now to FIG. 19D, after targeting the distal portion of thetumor from multiple directions, such as through 360 degrees, the outerperimeter of the tumor has been strongly irradiated with peak Braggprofile energy, the middle of the Bragg peak energy profile energy hasbeen delivered along an inner edge of the heavily irradiated tumorperimeter, and smaller dosages from the ingress portion of the Braggenergy profile are distributed throughout the tumor and into somehealthy tissue. The delivered dosages or accumulated radiation fluxlevels are illustrated in a cross-sectional area of the tumor 1420 usingan iso-line plot. After a first full rotation of the patient,symbolically, the darkest regions of the tumor are nearly fullyirradiated and the regions of the tissue having received less radiationare illustrated with a gray scale with the whitest portions having thelowest radiation dose.

Referring now to FIG. 19E, after completing the distal targetingmulti-field irradiation, a smaller inner tumor is defined, where theinner tumor is already partially irradiated. The smaller inner tumor isindicated by the dashed line 1930.

The above process of irradiating the tumor is repeated for the newlydefined smaller tumor. The proton dosages to the outer or distalportions of the smaller tumor are adjusted to account for the dosagesdelivered from other rotational positions. After the second tumor isirradiated, a yet smaller third tumor is defined. The process isrepeated until the entire tumor is irradiated at the prescribed ordefined dosage.

As described at the onset of this example, the patient is preferablyonly rotated to each rotational position once. In the above describedexample, after irradiation of the outer perimeter of the tumor, thepatient is rotationally positioned, such as through 360 degrees, and thedistal portion of the newest smaller tumor is targeted as described,supra. However, the irradiation dosage to be delivered to the secondsmaller tumor and each subsequently smaller tumor is known a-priori.Hence, when at a given angle of rotation, the smaller tumor or multipleprogressively smaller tumors, are optionally targeted so that thepatient is only rotated to the multiple rotational irradiation positionsonce.

The goal is to deliver a treatment dosage to each position of the tumor,to preferably not exceed the treatment dosage to any position of thetumor, to minimize ingress radiation dosage to healthy tissue, tocircumferentially distribute ingress radiation hitting the healthytissue, and to further minimize ingress radiation dosage to sensitiveareas. Since the Bragg energy profile is known, it is possible tocalculated the optimal intensity and energy of the proton beam for eachrotational position and for each x- and y-axis scanning position. Thesecalculation result in slightly less than threshold radiation dosage tobe delivered to the distal portion of the tumor for each rotationalposition as the ingress dose energy from other positions bring the totaldose energy for the targeted position up to the threshold delivery dose.

Referring again to FIG. 19A and FIG. 19C, the intensity of the protonbeam is preferably adjusted to account for the cross-sectional distanceor density of the healthy tissue. An example is used for clarity.Referring now to FIG. 19A, when irradiating from the first positionwhere the healthy tissue has a small area 1910, the intensity of theproton beam is preferably increased as relatively less energy isdelivered by the ingress portion of the Bragg profile to the healthytissue. Referring now to FIG. 19C, in contrast when irradiating from then^(th) rotational position where the healthy tissue has a largecross-sectional area 1920, the intensity of the proton beam ispreferably decreased as a greater fraction the proton dose is deliveredto the healthy tissue from this orientation.

In one example, for each rotational position and/or for each z-axisdistance into the tumor, the efficiency of proton dose delivery to thetumor is calculated. The intensity of the proton beam is madeproportional to the calculated efficiency. Essentially, when thescanning direction has really good efficiency, the intensity isincreased and vise-versa. For example, if the tumor is elongated,generally the efficiency of irradiating the distal portion by goingthrough the length of the tumor is higher than irradiating a distalregion of the tumor by going across the tumor with the Bragg energydistribution. Generally, in the optimization algorithm:

-   -   distal portions of the tumor are targeted for each rotational        position;    -   the intensity of the proton beam is largest with the largest        cross-sectional area of the tumor;    -   intensity is larger when the intervening healthy tissue volume        is smallest; and    -   intensity is minimized or cut to zero when the intervening        healthy tissue volume includes sensitive tissue, such as the        spinal cord or eyes.

Using an exemplary algorithm, the efficiency of radiation dose deliveryto the tumor is maximized. More particularly, the ratio of radiationdose delivered to the tumor versus the radiation dose delivered tosurrounding healthy tissue approaches a maximum. Further, integratedradiation dose delivery to each x, y, and z-axis volume of the tumor asa result of irradiation from multiple rotation directions is at or nearthe preferred dose level. Still further, ingress radiation dose deliveryto healthy tissue is circumferentially distributed about the tumor viause of multi-field irradiation where radiation is delivered from aplurality of directions into the body, such as more than 5, 10, 20, or30 directions.

In one example, the intensity of the charged particle beam correlateswith energy of the charged particle beam. For instance, if the roundtumor is exactly in the center of a healthy tissue volume, efficiency ofradiation delivery is maximized when targeting the distal region of thetumor from a given direction, which occurs with maximum energy. Whenradiation delivery is maximized, the intensity of the charged particlesis preferably maximized. Conversely, when the energy is targeting aproximal region of a tumor, then the efficiency of energy delivery tothe tumor is small as the ingress energy of the charged particle beam ishigher when striking healthy tissue. Thus, the intensity of the chargedparticle beam is preferably lower when the energy of the chargedparticle beam is lower. Preferably, a correlation coefficient of theintensity to the energy is at least 0.25 and preferably at least about0.5, 0.75, or 0.9. Generally, for a non-centrally placed tumor inhealthy tissue, for irradiation from one of a number of irradiationdirections, the intensity of the charged particle beam is increased asthe energy level of the charged particle beam is increased.

Multi-Field Irradiation

In one multi-field irradiation example, the particle therapy system witha synchrotron ring diameter of less than six meters includes ability to:

-   -   rotate the patient through about 360 degrees;    -   extract radiation in about 0.1 to 10 seconds;    -   scan vertically about 100 millimeters;    -   scan horizontally about 700 millimeters;    -   vary beam energy from about 30 to 330 MeV/second during        irradiation;    -   focus the proton beam from about 2 to 20 millimeters at the        tumor; and/or    -   complete multi-field irradiation of a tumor in less than about        1, 2, 4, or 6 minutes as measured from the time of initiating        proton delivery to the patient 1430.

Referring now to FIG. 20, two multi-field irradiation methods 2000 aredescribed. In the first method, the main controller 110 rotationallypositions 2010 the patient 1430 and subsequently irradiates 2020 thetumor 1420. The process is repeated until a multi-field irradiation planis complete. In the second method, the main controller 110simultaneously rotates and irradiates 2030 the tumor 1420 within thepatient 1430 until the multi-field irradiation plan is complete. Moreparticularly, the proton beam irradiation occurs while the patient 1430is being rotated.

The 3-dimensional scanning system of the proton spot focal point,described herein, is preferably combined with a rotation/raster method.The method includes layer wise tumor irradiation from many directions.During a given irradiation slice, the proton beam energy is continuouslychanged according to the tissue's density in front of the tumor toresult in the beam stopping point, defined by the Bragg peak, to alwaysbe inside the tumor and inside the irradiated slice. The novel methodallows for irradiation from many directions, referred to herein asmulti-field irradiation, to achieve the maximal effective dose at thetumor level while simultaneously significantly reducing possibleside-effects on the surrounding healthy tissues in comparison withexisting methods. Essentially, the multi-field irradiation systemdistributes dose-distribution at tissue depths not yet reaching thetumor.

Proton Beam Position Control

Referring now to FIG. 21, a beam delivery and tissue volume scanningsystem is illustrated. Presently, the worldwide radiotherapy communityuses a method of dose field forming using a pencil beam scanning system.In stark contrast, FIG. 21 illustrates a spot scanning system or tissuevolume scanning system. In the tissue volume scanning system, the protonbeam is controlled, in terms of transportation and distribution, usingan inexpensive and precise scanning system. The scanning system is anactive system, where the beam is focused into a spot focal point ofabout one-half, one, two, or three millimeters in diameter. The focalpoint is translated along two axes while simultaneously altering theapplied energy of the proton beam, which effectively changes the thirddimension of the focal point. The system is applicable in combinationwith the above described rotation of the body, which preferably occursin-between individual moments or cycles of proton delivery to the tumor.Optionally, the rotation of the body by the above described systemoccurs continuously and simultaneously with proton delivery to thetumor.

For example, in the illustrated system in FIG. 21A, the spot istranslated horizontally, is moved down a vertical y-axis, and is thenback along the horizontal axis. In this example, current is used tocontrol a vertical scanning system having at least one magnet. Theapplied current alters the magnetic field of the vertical scanningsystem to control the vertical deflection of the proton beam. Similarly,a horizontal scanning magnet system controls the horizontal deflectionof the proton beam. The degree of transport along each axes iscontrolled to conform to the tumor cross-section at the given depth. Thedepth is controlled by changing the energy of the proton beam. Forexample, the proton beam energy is decreased, so as to define a newpenetration depth, and the scanning process is repeated along thehorizontal and vertical axes covering a new cross-sectional area of thetumor. Combined, the three axes of control allow scanning or movement ofthe proton beam focal point over the entire volume of the canceroustumor. The time at each spot and the direction into the body for eachspot is controlled to yield the desired radiation does at eachsub-volume of the cancerous volume while distributing energy hittingoutside of the tumor.

The focused beam spot volume dimension is preferably tightly controlledto a diameter of about 0.5, 1, or 2 millimeters, but is alternativelyseveral centimeters in diameter. Preferred design controls allowscanning in two directions with: (1) a vertical amplitude of about 100mm amplitude and frequency up to about 200 Hz; and (2) a horizontalamplitude of about 700 mm amplitude and frequency up to about 1 Hz.

In FIG. 21A, the proton beam is illustrated along a z-axis controlled bythe beam energy, the horizontal movement is along an x-axis, and thevertical direction is along a y-axis. The distance the protons movealong the z-axis into the tissue, in this example, is controlled by thekinetic energy of the proton. This coordinate system is arbitrary andexemplary. The actual control of the proton beam is controlled in3-dimensional space using two scanning magnet systems and by controllingthe kinetic energy of the proton beam. The use of the extraction system,described supra, allows for different scanning patterns. Particularly,the system allows simultaneous adjustment of the x-, y-, and z-axes inthe irradiation of the solid tumor. Stated again, instead of scanningalong an x,y-plane and then adjusting energy of the protons, such aswith a range modulation wheel, the system allows for moving along thez-axes while simultaneously adjusting the x- and or y-axes. Hence,rather than irradiating slices of the tumor, the tumor is optionallyirradiated in three simultaneous dimensions. For example, the tumor isirradiated around an outer edge of the tumor in three dimensions. Thenthe tumor is irradiated around an outer edge of an internal section ofthe tumor. This process is repeated until the entire tumor isirradiated. The outer edge irradiation is preferably coupled withsimultaneous rotation of the subject, such as about a vertical y-axis.This system allows for maximum efficiency of deposition of protons tothe tumor, as defined as the ratio of the proton irradiation energydelivered to the tumor relative to the proton irradiation energydelivered to the healthy tissue.

Combined, the system allows for multi-axis control of the chargedparticle beam system in a small space with low power supply. Forexample, the system uses multiple magnets where each magnet has at leastone edge focusing effect in each turning section of the synchrotronand/or multiple magnets having concentrating magnetic field geometry, asdescribed supra. The multiple edge focusing effects in the circulatingbeam path of the synchrotron combined with the concentration geometry ofthe magnets and described extraction system yields a synchrotron having:

-   -   a small circumference system, such as less than about 50 meters;    -   a vertical proton beam size gap of about 2 cm;    -   corresponding reduced power supply requirements associated with        the reduced gap size;    -   an extraction system not requiring a newly introduced magnetic        field;    -   acceleration or deceleration of the protons during extraction;        and    -   control of z-axis energy during extraction.

The result is a 3-dimensional scanning system, x-, y-, and z-axescontrol, where the z-axes control resides in the synchrotron and wherethe z-axes energy is variably controlled during the extraction processinside the synchrotron.

Referring now to FIG. 21B, an example of a proton scanning or targetingsystem 140 used to direct the protons to the tumor with 4-dimensionalscanning control is provided, where the 4-dimensional scanning controlis along the x-, y-, and z-axes along with intensity control, asdescribed supra. A fifth axis is time. Typically, charged particlestraveling along the transport path 268 are directed through a first axiscontrol element 142, such as a vertical control, and a second axiscontrol element 144, such as a horizontal control and into a tumor 1420.As described, supra, the extraction system also allows for simultaneousvariation in the z-axis. Further, as describe, supra, the intensity ordose of the extracted beam is optionally simultaneously andindependently controlled and varied. Thus instead of irradiating a sliceof the tumor, as in FIG. 21A, all four dimensions defining the targetingspot of the proton delivery in the tumor are simultaneously variable.The simultaneous variation of the proton delivery spot is illustrated inFIG. 21B by the spot delivery path 269. In the illustrated case, theprotons are initially directed around an outer edge of the tumor and arethen directed around an inner radius of the tumor. Combined withrotation of the subject about a vertical axis, a multi-fieldillumination process is used where a not yet irradiated portion of thetumor is preferably irradiated at the further distance of the tumor fromthe proton entry point into the body. This yields the greatestpercentage of the proton delivery, as defined by the Bragg peak, intothe tumor and minimizes damage to peripheral healthy tissue.

Imaging/X-Ray System

Herein, an X-ray system is used to illustrate an imaging system.

Timing

An X-ray is preferably collected either (1) just before or (2)concurrently with treating a subject with proton therapy for a couple ofreasons. First, movement of the body, described supra, changes the localposition of the tumor in the body relative to other body constituents.If the subject has an X-ray taken and is then bodily moved to a protontreatment room, accurate alignment of the proton beam to the tumor isproblematic. Alignment of the proton beam to the tumor using one or moreX-rays is best performed at the time of proton delivery or in theseconds or minutes immediately prior to proton delivery and after thepatient is placed into a therapeutic body position, which is typically afixed position or partially immobilized position. Second, the X-raytaken after positioning the patient is used for verification of protonbeam alignment to a targeted position, such as a tumor and/or internalorgan position.

Positioning

An X-ray is preferably taken just before treating the subject to aid inpatient positioning. For positioning purposes, an X-ray of a large bodyarea is not needed. In one embodiment, an X-ray of only a local area iscollected. When collecting an X-ray, the X-ray has an X-ray path. Theproton beam has a proton beam path. Overlaying the X-ray path with theproton beam path is one method of aligning the proton beam to the tumor.However, this method involves putting the X-ray equipment into theproton beam path, taking the X-ray, and then moving the X-ray equipmentout of the beam path. This process takes time. The elapsed time whilethe X-ray equipment moves has a couple of detrimental effects. First,during the time required to move the X-ray equipment, the body moves.The resulting movement decreases precision and/or accuracy of subsequentproton beam alignment to the tumor. Second, the time required to movethe X-ray equipment is time that the proton beam therapy system is notin use, which decreases the total efficiency of the proton beam therapysystem.

X-Ray Source Lifetime

Preferably, components in the particle beam therapy system requireminimal or no maintenance over the lifetime of the particle beam therapysystem. For example, it is desirable to equip the proton beam therapysystem with an X-ray system having a long lifetime source, such as alifetime of about 20 years.

In one system, described infra, electrons are used to create X-rays. Theelectrons are generated at a cathode where the lifetime of the cathodeis temperature dependent. Analogous to a light bulb, where the filamentis kept in equilibrium, the cathode temperature is held in equilibriumat temperatures at about 200, 500, or 1000 degrees Celsius. Reduction ofthe cathode temperature results in increased lifetime of the cathode.Hence, the cathode used in generating the electrons is preferably heldat as low of a temperature as possible. However, if the temperature ofthe cathode is reduced, then electron emissions also decrease. Toovercome the need for more electrons at lower temperatures, a largecathode is used and the generated electrons are concentrated. Theprocess is analogous to compressing electrons in an electron gun;however, here the compression techniques are adapted to apply toenhancing an X-ray tube lifetime.

Referring now to FIG. 22, an example of an X-ray generation device 2200having an enhanced lifetime is provided. Electrons 2220 are generated ata cathode 2210, focused with a control electrode 2212, and acceleratedwith a series of accelerating electrodes 2240. The accelerated electrons2250 impact an X-ray generation source 2248 resulting in generatedX-rays that are then directed along an X-ray path 2370 to the subject1430. The concentrating of the electrons from a first diameter 2215 to asecond diameter 2216 allows the cathode to operate at a reducedtemperature and still yield the necessary amplified level of electronsat the X-ray generation source 2248. In one example, the X-raygeneration source is the anode coupled with the cathode 2210 and/or theX-ray generation source is substantially composed of tungsten.

Still referring to FIG. 22, a more detailed description of an exemplaryX-ray generation device 2200 is described. An anode 2214/cathode 2210pair is used to generated electrons. The electrons 2220 are generated atthe cathode 2210 having a first diameter 2215, which is denoted d₁. Thecontrol electrodes 2212 attract the generated electrons 2220. Forexample, if the cathode is held at about −150 kV and the controlelectrode is held at about −149 kV, then the generated electrons 2220are attracted toward the control electrodes 2212 and focused. A seriesof accelerating electrodes 2240 are then used to accelerate theelectrons into a substantially parallel path 2250 with a smallerdiameter 2116, which is denoted d₂. For example, with the cathode heldat −150 kV, a first, second, third, and fourth accelerating electrodes2242, 2244, 2246, 2248 are held at about −120, −90, −60, and −30 kV,respectively. If a thinner body part is to be analyzed, then the cathode2210 is held at a smaller level, such as about −90 kV and the controlelectrode, first, second, third, and fourth electrode are each adjustedto lower levels. Generally, the voltage difference from the cathode tofourth electrode is less for a smaller negative voltage at the cathodeand vise-versa. The accelerated electrons 2250 are optionally passedthrough a magnetic lens 2260 for adjustment of beam size, such as acylindrical magnetic lens. The electrons are also optionally focusedusing quadrupole magnets 2270, which focus in one direction and defocusin another direction. The accelerated electrons 2250, which are nowadjusted in beam size and focused strike an X-ray generation source2248, such as tungsten, resulting in generated X-rays that pass througha blocker 2362 and proceed along an X-ray path 2270 to the subject. TheX-ray generation source 2248 is optionally cooled with a cooling element2249, such as water touching or thermally connected to a backside of theX-ray generation source 2248. The concentrating of the electrons from afirst diameter 2215 to a second diameter 2216 allows the cathode tooperate at a reduced temperature and still yield the necessary amplifiedlevel of electrons at the X-ray generation source 2248.

More generally, the X-ray generation device 2200 produces electronshaving initial vectors. One or more of the control electrode 2212,accelerating electrodes 2240, magnetic lens 2260, and quadrupole magnets2270 combine to alter the initial electron vectors into parallel vectorswith a decreased cross-sectional area having a substantially parallelpath, referred to as the accelerated electrons 2250. The process allowsthe X-ray generation device 2200 to operate at a lower temperature.Particularly, instead of using a cathode that is the size of theelectron beam needed, a larger electrode is used and the resultingelectrons 2220 are focused and/or concentrated into the requiredelectron beam needed. As lifetime is roughly an inverse of currentdensity, the concentration of the current density results in a largerlifetime of the X-ray generation device. A specific example is providedfor clarity. If the cathode has a fifteen mm radius or d₁ is about 30mm, then the area (π r²) is about 225 mm² times pi. If the concentrationof the electrons achieves a radius of five mm or d₂ is about 10 mm, thenthe area (π r²) is about 25 mm² times pi. The ratio of the two areas isabout nine (225π/25π). Thus, there is about nine times less density ofcurrent at the larger cathode compared to the traditional cathode havingan area of the desired electron beam. Hence, the lifetime of the largercathode approximates nine times the lifetime of the traditional cathode,though the actual current through the larger cathode and traditionalcathode is about the same. Preferably, the area of the cathode 2210 isabout 2, 4, 6, 8, 10, 15, 20, or 25 times that of the cross-sectionalarea of the substantially parallel electron beam 2150.

In another embodiment of the invention, the quadrupole magnets 2270result in an oblong cross-sectional shape of the electron beam 2250. Aprojection of the oblong cross-sectional shape of the electron beam 2250onto the X-ray generation source 2248 results in an X-ray beam that hasa small spot in cross-sectional view, which is preferably substantiallycircular in cross-sectional shape, that is then passed through thepatient 1430. The small spot is used to yield an X-ray having enhancedresolution at the patient.

Referring now to FIG. 23, in one embodiment, an X-ray is generated closeto, but not in, the proton beam path. A proton beam therapy system andan X-ray system combination 2300 is illustrated in FIG. 23. The protonbeam therapy system has a proton beam 268 in a transport system afterthe Lamberson extraction magnet 292 of the synchrotron 130. The protonbeam is directed by the scanning/targeting/delivery system 140 to atumor 1420 of a patient 1430. The X-ray system 2305 includes an electronbeam source 2205 generating an electron beam 2250. The electron beam isdirected to an X-ray generation source 2248, such as a piece oftungsten. Preferably, the tungsten X-ray source is located about 1, 2,3, 5, 10, 15, 20, or 40 millimeters from the proton beam path 268. Whenthe electron beam 2250 hits the tungsten, X-rays are generated. In acase where the X-rays are generated in all directions, X-rays arepreferably blocked with a port 2362 and are selected for an X-ray beampath 2370. In a second case, the geometry of the electron beam 2250 andX-ray generation source 2248 yield generated X-rays 2270 having adirectionality, such as aligned with the proton beam 268. In eithercase, the X-ray beam path 2370 and proton beam path 268 runsubstantially in parallel as they progress to the tumor 1420. Thedistance between the X-ray beam path 2370 and proton beam path 269preferably diminishes to near zero and/or the X-ray beam path 2370 andproton beam path 269 overlap by the time they reach the tumor 1420.Simple geometry shows this to be the case given the long distance, of atleast a meter, between the tungsten and the tumor 1420. The distance isillustrated as a gap 2380 in FIG. 23. The X-rays are detected at anX-ray detector 2390, which is used to form an image of the tumor 1420and/or position of the patient 1430.

As a whole, the system generates an X-ray beam that lies insubstantially the same path as the proton therapy beam. The X-ray beamis generated by striking a tungsten or equivalent material with anelectron beam. The X-ray generation source is located proximate to theproton beam path. Geometry of the incident electrons, geometry of theX-ray generation material, and geometry of the X-ray beam blocker 262yield an X-ray beam that runs either in substantially in parallel withthe proton beam or results in an X-ray beam path that starts proximatethe proton beam path an expands to cover and transmit through a tumorcross-sectional area to strike an X-ray detector array or film allowingimaging of the tumor from a direction and alignment of the protontherapy beam. The X-ray image is then used to control the chargedparticle beam path to accurately and precisely target the tumor, and/oris used in system verification and validation.

Having an X-ray generation source 2248 that is proximate the proton beampath 268 allows for an X-ray of the patient 1430 to be collected closein time to use of the proton beam for tumor 1420 therapy as the X-raygeneration source 2248 need not be mechanically moved prior to protontherapy. For instance, proton irradiation of the tumor 1420 occurswithin about 1, 5, 10, 20, 30, or 60 seconds of when the X-ray iscollected.

Patient Immobilization

Accurate and precise delivery of a proton beam to a tumor of a patientrequires: (1) positioning control of the proton beam and (2) positioningcontrol of the patient. As described, supra, the proton beam iscontrolled using algorithms and magnetic fields to a diameter of about0.5, 1, or 2 millimeters. This section addresses partial immobilization,restraint, and/or alignment of the patient to insure the tightlycontrolled proton beam efficiently hits a target tumor and notsurrounding healthy tissue as a result of patient movement.

In this section an x-, y-, and z-axes coordinate system and rotationaxis is used to describe the orientation of the patient relative to theproton beam. The z-axis represent travel of the proton beam, such as thedepth of the proton beam into the patient. When looking at the patientdown the z-axis of travel of the proton beam, the x-axis refers tomoving left or right across the patient and the y-axis refers tomovement up or down the patient. A first rotation axis is rotation ofthe patient about the y-axis and is referred to herein as a rotationaxis, bottom unit 1412 rotation axis, or y-axis of rotation. Inaddition, tilt is rotation about the x-axis, yaw is rotation about they-axis, and roll is rotation about the z-axis. In this coordinatesystem, the proton beam path 269 optionally runs in any direction. As anillustrative matter, the proton beam path running through a treatmentroom is described as running horizontally through the treatment room.

In this section, a partial patient 1430 immobilization system 2400 isdescribed. A semi-vertical partial immobilization system is used toillustrate key features, which are illustrative of a features in asitting partial immobilization system or a laying positioning system.

Vertical Patient Positioning/Immobilization

Referring now to FIG. 24, the semi-vertical patient positioning system2400 is preferably used in conjunction with proton therapy of tumors inthe torso. The patient positioning and/or immobilization system controlsand/or restricts movement of the patient during proton beam therapy. Ina first partial immobilization embodiment, the patient is positioned ina semi-vertical position in a proton beam therapy system. Asillustrated, the patient is reclining at an angle alpha, α, about 45degrees off of the y-axis as defined by an axis running from head tofoot of the patient. More generally, the patient is optionallycompletely standing in a vertical position of zero degrees off the ofy-axis or is in a semi-vertical position alpha that is reclined about 5,10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or 65 degrees off of they-axis toward the z-axis.

Patient positioning constraints 2415 are used to maintain the patient ina treatment position, including one or more of: a seat support 2420, aback support 2430, a head support 2440, an arm support 2450, a kneesupport 2460, and a foot support 2470. The constraints are optionallyand independently rigid or semi-rigid. Examples of a semi-rigid materialinclude a high or low density foam or a visco-elastic foam. For examplethe foot support is preferably rigid and the back support is preferablysemi-rigid, such as a high density foam material. One or more of thepositioning constraints 2415 are movable and/or under computer controlfor rapid positioning and/or immobilization of the patient. For example,the seat support 2420 is adjustable along a seat adjustment axis 2422,which is preferably the y-axis; the back support 2430 is adjustablealong a back support axis 2432, which is preferably dominated by z-axismovement with a y-axis element; the head support 2440 is adjustablealong a head support axis 2442, which is preferably dominated by z-axismovement with a y-axis element; the arm support 2450 is adjustable alongan arm support axis 2452, which is preferably dominated by z-axismovement with a y-axis element; the knee support 2460 is adjustablealong a knee support axis 2462, which is preferably dominated by y-axismovement with a z-axis element; and the foot support 2470 is adjustablealong a foot support axis 2472, which is preferably dominated by y-axismovement with a z-axis element.

If the patient is not facing the incoming proton beam, then thedescription of movements of support elements along the axes change, butthe immobilization elements are the same.

An optional camera 2480 is used with the patient immobilization system.The camera views the patient/subject creating an video image. The imageis provided to one or more operators of the charged particle beam systemand allows the operators a safety mechanism for determining if thesubject has moved or desires to terminate the proton therapy treatmentprocedure. Based on the video image, the operators may suspend orterminate the proton therapy procedure. For example, if the operatorobserves via the video image that the subject is moving, then theoperator has the option to terminate or suspend the proton therapyprocedure.

An optional video display 2490 is provided to the patient. The videodisplay optionally presents to the patient any of: operatorinstructions, system instructions, status of treatment, orentertainment.

Motors for positioning the constraints 2415, the camera 2480, and videodisplay 2490 are preferably mounted above or below the proton path.

Respiration control is optionally performed by using the video display.As the patient breathes, internal and external structures of the bodymove in both absolute terms and in relative terms. For example, theoutside of the chest cavity and internal organs both have absolute moveswith a breath. In addition, the relative position of an internal organrelative to another body component, such as an outer region of the body,a bone, support structure, or another organ, moves with each breath.Hence, for more accurate and precise tumor targeting, the proton beam ispreferably delivered at point a in time where the position of theinternal structure or tumor is well defined, such as at the bottom ofeach breath. The video display is used to help coordinate the protonbeam delivery with the patient's breathing cycle. For example, the videodisplay optionally displays to the patient a command, such as a holdbreath statement, a breath statement, a countdown indicating when abreadth will next need to be held, or a countdown until breathing mayresume.

The semi-vertical patient positioning system 2400 and sitting patientpositioning system are preferentially used to treatment of tumors in thehead or torso due to efficiency. The semi-vertical patient positioningsystem 2400, sitting patient positioning system, and laying patientpositioning system are all usable for treatment of tumors in thepatient's limbs.

Support System Elements

Positioning constraints 2415 include all elements used to position thepatient, such as those described in the semi-vertical positioning system2400, sitting positioning system, and laying positioning system.Preferably, positioning constraints or support system elements arealigned in positions that do not impede or overlap the proton beam path269. However, in some instances the positioning constraints are in theproton beam path 269 during at least part of the time of treatment ofthe patient. For instance, a positioning constraint element may residein the proton beam path 269 during part of a time period where thepatient is rotated about the y-axis during treatment. In cases or timeperiods that the positioning constraints or support system elements arein the proton beam path, then an upward adjustment of proton beam energyis preferably applied that increases the proton beam energy to offsetthe positioning constraint element impedance of the proton beam. In onecase, the proton beam energy is increased by a separate measure of thepositioning constraint element impedance determined during a referencescan of the positioning constraint system element or set of referencescans of the positioning constraint element as a function of rotationabout the y-axis.

For clarity, the positioning constraints 2415 or support system elementsare herein described relative to the semi-vertical positioning system2400; however, the positioning elements and descriptive x-, y-, andz-axes are adjustable to fit any coordinate system, to the sittingpositioning system, or the laying positioning system.

An example of a head support system is described to support, align,and/or restrict movement of a human head. The head support systempreferably has several head support elements including any of: a back ofhead support, a right of head alignment element, and a left of headalignment element. The back of head support element is preferably curvedto fit the head and is optionally adjustable along a head support axis,such as along the z-axis. Further, the head supports, like the otherpatient positioning constraints, is preferably made of a semi-rigidmaterial, such as a low or high density foam, and has an optionalcovering, such as a plastic or leather. The right of head alignmentelement and left of head alignment elements or head alignment elements,are primarily used to semi-constrain movement of the head. The headalignment elements are preferably padded and flat, but optionally have aradius of curvature to fit the side of the head. The right and left headalignment elements are preferably respectively movable along translationaxes to make contact with the sides of the head. Restricted movement ofthe head during proton therapy is important when targeting and treatingtumors in the head or neck. The head alignment elements and the back ofhead support element combine to restrict tilt, rotation or yaw, rolland/or position of the head in the x-, y-, z-axes coordinate system.

Referring now to FIG. 25 another example of a head support system 2500is described for positioning and/or restricting movement of a human head1402 during proton therapy of a solid tumor in the head or neck. In thissystem, the head is restrained using 1, 2, 3, 4, or more straps orbelts, which are preferably connected or replaceably connected to a backof head support element 2510. In the example illustrated, a first strap2520 pulls or positions the forehead to the head support element 2510,such as by running predominantly along the z-axis. Preferably a secondstrap 2530 works in conjunction with the first strap 2520 to prevent thehead from undergoing tilt, yaw, roll or moving in terms of translationalmovement on the x-, y-, and z-axes coordinate system. The second strap2530 is preferably attached or replaceable attached to the first strap2520 at or about: (1) the forehead 2532; (2) on one or both sides of thehead 2534; and/or (3) at or about the support element 2510. A thirdstrap 2540 preferably orientates the chin of the subject relative to thesupport element 2510 by running dominantly along the z-axis. A fourthstrap 2550 preferably runs along a predominantly y- and z-axes to holdthe chin relative to the head support element 2510 and/or proton beampath. The third 2540 strap preferably is attached to or is replaceablyattached to the fourth strap 2550 during use at or about the patient'schin 2542. The second strap 2530 optionally connects 2536 to the fourthstrap 2550 at or about the support element 2510. The four straps 2520,2530, 2540, 2550 are illustrative in pathway and interconnection. Any ofthe straps optionally hold the head along different paths around thehead and connect to each other in separate fashion. Naturally, a givenstrap preferably runs around the head and not just on one side of thehead. Any of the straps 2520, 2530, 2540, and 2550 are optionally usedindependently or in combinations and permutations with the other straps.The straps are optionally indirectly connected to each other via asupport element, such as the head support element 2510. The straps areoptionally attached to the head support element 2510 using hook and looptechnology, a buckle, or fastener. Generally, the straps combine tocontrol position, front-to-back movement of the head, side-to-sidemovement of the head, tilt, yaw, roll, and/or translational position ofthe head.

The straps are preferably of known impedance to proton transmissionallowing a calculation of peak energy release along the z-axis to becalculated. For example, adjustment to the Bragg peak energy is madebased on the slowing tendency of the straps to proton transport.

Positioning System Computer Control

One or more of the patient positioning unit components and/or one ofmore of the patient positioning constraints are preferably undercomputer control, where the computer control positioning devices, suchas via a series of motors and drives, to reproducibly position thepatient. For example, the patient is initially positioned andconstrained by the patient positioning constraints. The position of eachof the patient positioning constraints is recorded and saved by the maincontroller 110, by a sub-controller or the main controller 110, or by aseparate computer controller. Then, medical devices are used to locatethe tumor 1420 in the patient 1430 while the patient is in theorientation of final treatment. The imaging system 170 includes one ormore of: MRI's, X-rays, CT's, proton beam tomography, and the like. Timeoptionally passes at this point where images from the imaging system 170are analyzed and a proton therapy treatment plan is devised. The patientmay exit the constraint system during this time period, which may beminutes, hours, or days. Upon return of the patient to the patientpositioning unit, the computer can return the patient positioningconstraints to the recorded positions. This system allows for rapidrepositioning of the patient to the position used during imaging anddevelopment of the treatment plan, which minimizes setup time of patientpositioning and maximizes time that the charged particle beam system 100is used for cancer treatment.

Patient Placement

Preferably, the patient 1430 is aligned in the proton beam path 269 in aprecise and accurate manner. Several placement systems are described.The patient placement systems are described using the laying positioningsystem, but are equally applicable to the semi-vertical and sittingpositioning systems.

In a first placement system, the patient is positioned in a knownlocation relative to the platform. For example, one or more of thepositioning constraints position the patient in a precise and/oraccurate location on the platform. Optionally, a placement constraintelement connected or replaceably connected to the platform is used toposition the patient on the platform. The placement constraintelement(s) is used to position any position of the patient, such as ahand, limb, head, or torso element.

In a second placement system, one or more positioning constraints, orsupport element, such as the platform, is aligned versus an element inthe patient treatment room. Essentially a lock and key system isoptionally used, where a lock fits a key. The lock and key elementscombine to locate the patient relative to the proton beam path 269 interms of any of the x-, y-, and z-position, tilt, yaw, and roll.Essentially the lock is a first registration element and the key is asecond registration element fitting into, adjacent to, or with the firstregistration element to fix the patient location and/or a supportelement location relative to the proton beam path 269. Examples of aregistration element include any of a mechanical element, such as amechanical stop, and an electrical connection indicating relativeposition or contact.

In a third placement system, the imaging system, described supra, isused to determine where the patient is relative to the proton beam path269 or relative to an imaging marker placed in an support element orstructure holding the patient, such as in the platform. When using theimaging system, such as an X-ray imaging system, then the firstplacement system or positioning constraints minimize patient movementonce the imaging system determines location of the subject. Similarly,when using the imaging system, such as an X-ray imaging system, then thefirst placement system and/or second positioning system provide a crudeposition of the patient relative to the proton beam path 269 and theimaging system subsequently determines a fine position of the patientrelative to the proton beam path 269.

X-Ray Synchronization with Patient Respiration

In one embodiment, X-ray images are collected in synchronization withpatient respiration or breathing. The synchronization enhances X-rayimage clarity by removing position ambiguity due to the relativemovement of body constituents during a patient breathing cycle.

In a second embodiment, an X-ray system is orientated to provide X-rayimages of a patient in the same orientation as viewed by a protontherapy beam, is synchronized with patient breathing, is operable on apatient positioned for proton therapy, and does not interfere with aproton beam treatment path. Preferably, the synchronized system is usedin conjunction with a negative ion beam source, synchrotron, and/ortargeting method apparatus to provide an X-ray timed with patientbreathing and performed immediately prior to and/or concurrently withparticle beam therapy irradiation to ensure targeted and controlleddelivery of energy relative to a patient position resulting inefficient, precise, and/or accurate noninvasive, in-vivo treatment of asolid cancerous tumor with minimization of damage to surrounding healthytissue in a patient using the proton beam position verification system.

An X-ray delivery control algorithm is used to synchronize delivery ofthe X-rays to the patient 1430 within a given period of each breath,such as at the top or bottom of a breath when the subject is holdingtheir breath. For clarity of combined X-ray images, the patient ispreferably both accurately positioned and precisely aligned relative tothe X-ray beam path 2370. The X-ray delivery control algorithm ispreferably integrated with the breathing control module. Thus, the X-raydelivery control algorithm knows when the subject is breathing, where inthe breath cycle the subject is, and/or when the subject is holdingtheir breath. In this manner, the X-ray delivery control algorithmdelivers X-rays at a selected period of the breathing cycle. Accuracyand precision of patient alignment allow for (1) more accurate andprecise location of the tumor 1420 relative to other body constituentsand (2) more accurate and precise combination of X-rays in generation ofa 3-dimensional X-ray image of the patient 1430 and tumor 1420.

Patient Respiration Monitoring

Preferably, the patient's respiration pattern is monitored. When asubject or patient 1430 is breathing many portions of the body move witheach breath. For example, when a subject breathes the lungs move as dorelative positions of organs within the body, such as the stomach,kidneys, liver, chest muscles, skin, heart, and lungs. Generally, mostor all parts of the torso move with each breath. Indeed, the inventorshave recognized that in addition to motion of the torso with eachbreath, various motion also exists in the head and limbs with eachbreath. Motion is to be considered in delivery of a proton dose to thebody as the protons are preferentially delivered to the tumor and not tosurrounding tissue. Motion thus results in an ambiguity in where thetumor resides relative to the beam path. To partially overcome thisconcern, protons are preferentially delivered at the same point in eachof a series of breathing cycles.

Initially a rhythmic pattern of respiration or breathing of a subject isdetermined. The cycle is observed or measured. For example, an X-raybeam operator or proton beam operator can observe when a subject isbreathing or is between breaths and can time the delivery of the protonsto a given period of each breath. Alternatively, the subject is told toinhale, exhale, and/or hold their breath and the protons are deliveredduring the commanded time period.

Preferably, one or more sensors are used to determine the breathingcycle of the individual. Two examples of a breath monitoring system areprovided: (1) a thermal monitoring system and (2) a force monitoringsystem.

A first example of the thermal breath monitoring system is provided. Inthe thermal breath monitoring system, a sensor 2470 is placed by thenose and/or mouth of the patient. As the jaw of the patient isoptionally constrained, as described supra, the thermal breathmonitoring system is preferably placed by the patient's nose exhalationpath. To avoid steric interference of the thermal sensor systemcomponents with proton therapy, the thermal breath monitoring system ispreferably used when treating a tumor not located in the head or neck,such as a when treating a tumor in the torso or limbs. In the thermalmonitoring system, a first thermal resistor 2570 is used to monitor thepatient's breathing cycle and/or location in the patient's breathingcycle. Preferably, the first thermal resistor 2570 is placed by thepatient's nose, such that the patient exhaling through their nose ontothe first thermal resistor 2570 warms the first thermal resistor 2570indicating an exhale. Preferably, a second thermal resistor 2560operates as an environmental temperature sensor. The second thermalresistor 2560 is preferably placed out of the exhalation path of thepatient but in the same local room environment as the first thermalresistor 2570. Generated signal, such as current from the thermalresistors 2570, is preferably converted to voltage and communicated withthe main controller 110 or a sub-controller of the main controller.Preferably, the second thermal resistor is used to adjust for theenvironmental temperature fluctuation that is part of a signal of thefirst thermal resistor 2570, such as by calculating a difference betweenvalues of the thermal resistors 2560, 2570 to yield a more accuratereading of the patient's breathing cycle.

A second example of the force/pressure breath monitoring system isprovided. In the force breath monitoring system, a sensor is placed bythe torso. To avoid steric interference of the force sensor systemcomponents with proton therapy, the force breath monitoring system ispreferably used when treating a tumor located in the head, neck, orlimbs. In the force monitoring system, a belt or strap 2455 is placedaround an area of the patient's torso that expands and contracts witheach breath cycle of the patient. The belt 2455 is preferably tightabout the patient's chest and is flexible. A force meter 2457 isattached to the belt and senses the patients breathing pattern. Theforces applied to the force meter 2457 correlate with periods of thebreathing cycle. The signals from the force meter 2457 are preferablycommunicated with the main controller 110 or a sub-controller of themain controller.

Respiration Control

Once the rhythmic pattern of the subject's respiration or breathing isdetermined, a signal is optionally delivered to the subject to moreprecisely control the breathing frequency. For example, a display screen2490 is placed in front of the subject directing the subject when tohold their breath and when to breath. Typically, a respiration controlmodule uses input from one or more of the breathing sensors. Forexample, the input is used to determine when the next breath exhale isto complete. At the bottom of the breath, the control module displays ahold breath signal to the subject, such as on a monitor, via an oralsignal, digitized and automatically generated voice command, or via avisual control signal. Preferably, a display monitor 2490 is positionedin front of the subject and the display monitor displays breathingcommands to the subject. Typically, the subject is directed to holdtheir breath for a short period of time, such as about ½, 1, 2, 3, 5, or10 seconds. The period of time the breath is held is preferablysynchronized to the delivery time of the proton beam to the tumor, whichis about ½, 1, 2, or 3 seconds. While delivery of the protons at thebottom of the breath is preferred, protons are optionally delivered atany point in the breathing cycle, such as upon full inhalation. Deliveryat the top of the breath or when the patient is directed to inhaledeeply and hold their breath by the respiration control module isoptionally performed as at the top of the breath the chest cavity islargest and for some tumors the distance between the tumor andsurrounding tissue is maximized or the surrounding tissue is rarefied asa result of the increased volume. Hence, protons hitting surroundingtissue is minimized. Optionally, the display screen tells the subjectwhen they are about to be asked to hold their breath, such as with a 3,2, 1, second countdown so that the subject is aware of the task they areabout to be asked to perform.

Proton Beam Therapy Synchronization with Respiration

A proton delivery control algorithm is used to synchronize delivery ofthe protons to the tumor within a given period of each breath, such asat the top or bottom of a breath when the subject is holding theirbreath. The proton delivery control algorithm is preferably integratedwith the respiration control module. Thus, the proton delivery controlalgorithm knows when the subject is breathing, where in the breath cyclethe subject is, and/or when the subject is holding their breath. Theproton delivery control algorithm controls when protons are injectedand/or inflected into the synchrotron, when an RF signal is applied toinduce an oscillation, as described supra, and when a DC voltage isapplied to extract protons from the synchrotron, as described supra.Typically, the proton delivery control algorithm initiates protoninflection and subsequent RF induced oscillation before the subject isdirected to hold their breath or before the identified period of thebreathing cycle selected for a proton delivery time. In this manner, theproton delivery control algorithm can deliver protons at a selectedperiod of the breathing cycle by simultaneously or nearly simultaneouslydelivering the high DC voltage to the second pair of plates, describedsupra, which results in extraction of the protons from the synchrotronand subsequent delivery to the subject at the selected time point. Sincethe period of acceleration of protons in the synchrotron is constant orknown for a desired energy level of the proton beam, the proton deliverycontrol algorithm is used to set an AC RF signal that matches thebreathing cycle or directed breathing cycle of the subject.

Developing and Implementing a Tumor Irradiation Plan

A series of steps are performed to design and execute a radiationtreatment plan for treating a tumor 1420 in a patient 1430. The stepsinclude one or more of:

-   -   positioning and immobilizing the patient;    -   recording the patient position;    -   monitoring patient breathing;    -   controlling patient breathing;    -   collecting multi-field images of the patient to determine tumor        location relative to body constituents;    -   developing a radiation treatment plan;    -   repositioning the patient;    -   verifying tumor location; and    -   irradiating the tumor.

In this section, an overview of developing the irradiation plan andsubsequent implementation of the irradiation plan is initiallypresented, the individual steps are further described, and a moredetailed example of the process is then described.

Referring now to FIG. 26, an overview of a system for development of anirradiation plan and subsequent implementation of the irradiation plan2600 is provided. Preferably, all elements of the positioning,respiration monitoring, imaging, and tumor irradiation system 2600 areunder main controller 110 control.

Initially, the tumor containing volume of the patient 1430 is positionedand immobilized 2610 in a controlled and reproducible position. Theprocess of positioning and immobilizing 2610 the patient 1430 ispreferably iterated 2612 until the position is accepted. The position ispreferably digitally recorded 2615 and is later used in a step ofcomputer controlled repositioning of the patient 2617 in the minutes orseconds prior to implementation of the irradiation element 2670 of thetumor treatment plan. The process of positioning the patient in areproducible fashion and reproducibly aligning the patient 1430 to thecontrolled position is further described, infra.

Subsequent to patient positioning 2610, the steps of monitoring 2620 andpreferably controlling 2630 the respiration cycle of the patient 1430are preferably performed to yield more precise positioning of the tumor1420 relative to other body constituents, as described supra.Multi-field images of the tumor are then collected 2640 in thecontrolled, immobilized, and reproducible position. For example,multi-field X-ray images of the tumor 1420 are collected using the X-raysource proximate the proton beam path, as described supra. Themulti-field images are optionally from three or more positions and/orare collected while the patient is rotated, as described supra.

At this point the patient 1430 is either maintained in the treatmentposition or is allowed to move from the controlled treatment positionwhile an oncologist processes the multi-field images 2645 and generatesa tumor treatment plan 2650 using the multi-field images. Optionally,the tumor irradiation plan is implemented 2670 at this point in time.

Typically, in a subsequent treatment center visit, the patient 1430 isrepositioned 2617. Preferably, the patient's respiration cycle is againmonitored 2622 and/or controlled 2632, such as via use of the thermalmonitoring respiration sensors, force monitoring respiration sensor,and/or via commands sent to the display monitor 2490, described supra.Once repositioned, verification images are collected 2660, such as X-raylocation verification images from 1, 2, or 3 directions. For example,verification images are collected with the patient facing the protonbeam and at rotation angles of 90, 180, and 270 degrees from thisposition. At this point, comparing the verification images to theoriginal multi-field images used in generating the treatment plan, thealgorithm or preferably the oncologist determines if the tumor 1420 issufficiently repositioned 2665 relative to other body parts to allow forinitiation of tumor irradiation using the charged particle beam.Essentially, the step of accepting the final position of the patient2665 is a safety feature used to verify that that the tumor 1420 in thepatient 1430 has not shifted or grown beyond set specifications. At thispoint the charged particle beam therapy commences 2670. Preferably thepatient's respiration is monitored 2624 and/or controlled 2634, asdescribed supra, prior to commencement of the charged particle beamtreatment 2670.

Optionally, simultaneous X-ray imaging 2690 of the tumor 1420 isperformed during the multi-field proton beam irradiation procedure andthe main controller 110 uses the X-ray images to adapt the radiationtreatment plan in real-time to account for small variations in movementof the tumor 1420 within the patient 1430.

Herein the step of monitoring 2620, 2622, 2624 and controlling 2630,2632, 2634 the patient's respiration is optional, but preferred. Thesteps of monitoring and controlling the patient's respiration areperformed before and/or during the multi-filed imaging 2640, positionverification 2660, and/or tumor irradiation 2670 steps.

The patient positioning 2610 and patient repositioning 2617 steps arefurther described, infra.

Coordinated Charged Particle Acceleration and Respiration Rate

In yet another embodiment, the charged particle accelerator issynchronized to the patient's respiration cycle. More particularly,synchrotron acceleration cycle usage efficiency is enhanced by adjustingthe synchrotron's acceleration cycle to correlate with a patient'srespiration rate. Herein, efficiency refers to the duty cycle, thepercentage of acceleration cycles used to deliver charged particles tothe tumor, and/or the fraction of time that charged particles aredelivered to the tumor from the synchrotron. The system senses patientrespiration and controls timing of negative ion beam formation,injection of charged particles into a synchrotron, acceleration of thecharged particles, and/or extraction to yield delivery of the particlesto the tumor at a predetermine period of the patient's respirationcycle. Preferably, one or more magnetic fields in the synchrotron 130are stabilized through use of a feedback loop, which allows rapidchanging of energy levels and/or timing of extraction from pulse topulse. Further, the feedback loop allows control of theacceleration/extraction to correlate with a changing patient respirationrate. Independent control of charged particle energy and intensity ismaintained during the timed irradiation therapy. Multi-field irradiationensures efficient delivery of Bragg peak energy to the tumor whilespreading ingress energy about the tumor.

In one example, a sensor, such as the first thermal sensor 2570 or thesecond thermal sensor 2560, is used to monitor a patient's respiration.A controller, such as the main controller 110, then controls chargedparticle formation and delivery to yield a charged particle beamdelivered at a determined point or duration period of the respirationcycle, which ensures precise and accurate delivery of radiation to atumor that moves during the respiration process. Optional chargedparticle therapy elements controlled by the controller include theinjector 120, accelerator 132, and/or extraction 134 system. Elementsoptionally controlled in the injector system 120 include: injection ofhydrogen gas into a negative ion source 310, generation of a high energyplasma within the negative ion source, filtering of the high energyplasma with a magnetic field, extracting a negative ion from thenegative ion source, focusing the negative ion beam 319, and/orinjecting a resulting positive ion beam 262 into the synchrotron 130.Elements optionally controlled in the accelerator 132 include:accelerator coils, applied magnetic fields in turning magnets, and/orapplied current to correction coils in the synchrotron. Elementsoptionally controlled in the extraction system 134 include:radio-frequency fields in an extraction element and/or applied fields inan extraction process. By using the respiration sensor to controldelivery of the charged particle beam to the tumor during a set periodof the respiration cycle, the period of delivery of the charged particleto the tumor is adjustable to a varying respiration rate. Thus, if thepatient breathes faster, the charged particle beam is delivered to thetumor more frequently and if the patient breathes slower, then thecharged particle beam is delivered to the tumor less frequently.Optionally, the charged particle beam is delivered to the tumor witheach breath of the patient regardless of the patient's changingrespiration rate. This lies in stark contrast with a system where thecharged particle beam delivers energy at a fixed time interval and thepatient must adjust their respiration rate to match the period of theaccelerator delivering energy and if the patient's respiration rate doesnot match the fixed period of the accelerator, then that acceleratorcycle is not delivered to the tumor and the acceleration usageefficiency is reduced.

Typically, in an accelerator the current is stabilized. A problem withcurrent stabilized accelerators is that the magnets used have memoriesin terms of both magnitude and amplitude of a sine wave. Hence, in atraditional system, in order to change the circulation frequency of thecharged particle beam in a synchrotron, slow changes in current must beused. However, in a second example, the magnetic field controlling thecirculation of the charged particles about the synchrotron isstabilized. The magnetic field is stabilized through use of: (1)magnetic field sensors sensing the magnetic field about the circulatingcharged particles and (2) a feedback loop through a controller or maincontroller 110 controlling the magnetic field about the circulatingcharged particles. The feedback loop is optionally used as a feedbackcontrol to the first winding coil 850 and the second winding coil 860.However, preferably the feedback loop is used to control the correctioncoils 852, 862, described supra. With the use of the feedback loopdescribed herein using the magnetic field sensors, the frequency andenergy level of the synchrotron are rapidly adjustable and the problemis overcome. Further, the use of the smaller correction coils 852, 862allows for rapid adjustment of the accelerator compared to the use ofthe larger winding coils 850, 860, described supra. More particularly,the feedback control allows an adjustment of the accelerator energy frompulse to pulse in the synchrotron 130.

In this section, the first example yielded delivery of the chargedparticle beam during a particular period of the patient's respirationcycle even if the patient's respiration period is varying. In thissection, the second example used a magnetic field sensor and a feedbackloop to the correction coils 852, 862 to rapidly adjust the energy ofthe accelerator from pulse to pulse. In a third example, the respirationsensor of the first example is combined with the magnetic field sensorof the second example to control both the timing of the delivery of thecharged particle beam from the accelerator and the energy of the chargedparticle beam from the accelerator. More particularly, the timing of thecharged particle delivery is controlled using the respiration sensor, asdescribed supra, and the energy of the charged particle beam iscontrolled using the magnetic filed sensors and feedback loop, asdescribed supra. Still more particularly, a magnetic field controller,such as the main controller 110, takes the input from the respirationsensor and uses the input as: (1) a feedback control to the magneticfields controlling the circulating charged particles energy and (2) as afeedback control to time the pulse of the charged particle acceleratorto the breathing cycle of the patient. This combination allows deliveryof the charged particle beam to the tumor with each breath of thepatient even if the breathing rate of the patient varies. In thismanner, the accelerator efficiency is increased as the cancer therapysystem does not need to lose cycles when the patient's breathing is notin phase with the synchrotron charged particle generation rate.

Referring now to FIG. 27, the combined use of the respiration sensor andmagnetic field sensor 2700 to deliver charged particles at varyingenergy and at varying time intervals is further described. The maincontroller 110 controls the injection system 120, charged particleacceleration system 132, extraction system 134, and targeting/deliverysystem 140. In this embodiment, a respiration monitoring system 2710 ofthe patient interface module 150 is used as an input to a magnetic fieldcontroller 2720. A second input to the magnetic field controller 2720 isa magnetic field sensor 2750. In one case, the respiration rates fromthe respiration monitoring system 2710 are fed to the main controller130, which controls the injection system 120 and/or components of theacceleration system 132 to yield a charged particle beam at a chosenperiod of the respiration cycle, as described supra. In a second case,the respiration data from the respiration monitoring system is used asan input to the magnetic field controller 2720. The magnetic fieldcontroller also receives feedback input from the magnetic field sensor2750. The magnetic field controller thus times charged particle energydelivery to correlate with sensed respiration rates and delivers energylevels of the charged particle beam that are rapidly adjustable witheach pulse of the accelerator using the feedback loop through themagnetic field sensor 2750.

Referring still to FIG. 27 and now additionally referring to FIG. 28, afurther example is used to clarify the magnetic field control using afeedback loop 2700 to change delivery times and/or periods of protonpulse delivery. In one case, a respiratory sensor 2710 senses therespiration cycle of the patient. The respiratory sensor sends thepatient's breathing pattern or information to an algorithm in themagnetic field controller 2720, typically via the patient interfacemodule 150 and/or via the main controller 110 or a subcomponent thereof.The algorithm predicts and/or measures when the patient is at aparticular point in the breathing cycle, such as at the top or bottom ofa breath. One or more magnetic field sensors 2750 are used as inputs tothe magnetic field controller 2720, which controls a magnet power supplyfor a given magnetic, such as within a first turning magnet 420 of asynchrotron 130. The control feedback loop is thus used to dial thesynchrotron to a selected energy level and to deliver protons with thedesired energy at a selected point in time, such as at a particularpoint in the respiration cycle. The selected point in the respirationcycle is optionally anywhere in the respiration cycle and/or for anyduration during the respiration cycle. As illustrated in FIG. 28, theselected time period is at the top of a breath for a period of about0.1, 0.5, 1 seconds. More particularly, the main controller 110 controlsinjection of hydrogen into the injection system, formation of thenegative ion 310, controls extraction of negative ions from negative ionsource 310, controls injection 120 of protons into the synchrotron 130,and/or controls acceleration of the protons in a manner that combinedwith extraction 134 delivers the protons 140 to the tumor at a selectedpoint in the respiration cycle. Intensity of the proton beam is alsoselectable and controllable by the main controller 130 at this stage, asdescribed supra. The feedback control from the magnetic field controller2720 is optionally to a power or power supplies for one or both of themain bending magnet 250, described supra, or to the correction coils852, 862 within the main bending magnet 250. Having smaller appliedcurrents, the correction coils 852, 862 are rapidly adjustable to anewly selected acceleration frequency or corresponding charged particleenergy level. Particularly, the magnetic field controller 2720 altersthe applied fields to the main bending magnets or correction coils thatare tied to the patient's respiration cycle. This system is in starkcontrast to a system where the current is stabilized and the synchrotrondelivers pulses with a fixed period. Preferably, the feedback of themagnetic field design coupled with the correction coils allows for theextraction cycle to match the varying respiratory rate of the patient,such as where a first respiration period 2810, P₁, does not equal asecond respiration period 2820, P₂.

Computer Controlled Patient Repositioning

One or more of the patient positioning unit components and/or one ofmore of the patient positioning constraints are preferably undercomputer control. For example, the computer records or controls theposition of the patient positioning elements 2415, such as via recordinga series of motor positions connected to drives that move the patientpositioning elements 2415. For example, the patient is initiallypositioned 2610 and constrained by the patient positioning constraints2415. The position of each of the patient positioning constraints isrecorded and saved by the main controller 110, by a sub-controller ofthe main controller 110, or by a separate computer controller. Then,imaging systems are used to locate the tumor 1420 in the patient 1430while the patient is in the controlled position of final treatment.Preferably, when the patient is in the controlled position, multi-fieldimaging is performed, as described herein. The imaging system 170includes one or more of: MRI's, X-rays, CT's, proton beam tomography,and the like. Time optionally passes at this point while images from theimaging system 170 are analyzed and a proton therapy treatment plan isdevised. The patient optionally exits the constraint system during thistime period, which may be minutes, hours, or days. Upon, and preferablyafter, return of the patient and initial patient placement into thepatient positioning unit, the computer returns the patient positioningconstraints to the recorded positions. This system allows for rapidrepositioning of the patient to the position used during imaging anddevelopment of the multi-field charged particle irradiation treatmentplan, which minimizes setup time of patient positioning and maximizestime that the charged particle beam system 100 is used for cancertreatment.

Reproducing Patient Positioning and Immobilization

In one embodiment, using a patient positioning and immobilization system2400, a region of the patient 1430 about the tumor 1420 is reproduciblypositioned and immobilized, such as with the motorized patienttranslation and rotation positioning system and/or with the patientpositioning constraints 1415. For example, one of the above describedpositioning systems 2400, such as (1) the semi-vertical partialimmobilization system; (2) the sitting partial immobilization system; or(3) the laying position system is used in combination with the patienttranslation and rotation system to position the tumor 1420 of thepatient 1430 relative to the proton beam path 268. Preferably, theposition and immobilization system 2400 controls position of the tumor1420 relative to the proton beam path 268, immobilizes position of thetumor 1420, and facilitates repositioning the tumor 1420 relative to theproton beam path 268 after the patient 1430 has moved away from theproton beam path 268, such as during development of the irradiationtreatment plan 2650.

Preferably, the tumor 1420 of the patient 1430 is positioned in terms of3-D location and in terms of orientation attitude. Herein, 3-D locationis defined in terms of the x-, y-, and z-axes and orientation attitudeis the state of pitch, yaw, and roll. Roll is rotation of a plane aboutthe z-axis, pitch is rotation of a plane about the x-axis, and yaw isthe rotation of a plane about the y-axis. Tilt is used to describe bothroll and pitch. Preferably, the positioning and immobilization system2400 controls the tumor 1420 location relative to the proton beam path268 in terms of at least three of and preferably in terms of four, five,or six of: pitch, yaw, roll, x-axis location, y-axis location, andz-axis location.

Chair

The patient positioning and immobilization system 2400 is furtherdescribed using a chair positioning example. For clarity, a case ofpositioning and immobilizing a tumor in a shoulder is described usingchair positioning. Using the semi-vertical immobilization system, thepatient is generally positioned using the seat support 2420, kneesupport 2460, and/or foot support 2470. To further position theshoulder, a motor in the back support 2430 pushes against the torso ofthe patient. Additional arm support 2450 motors align the arm, such asby pushing with a first force in one direction against the elbow of thepatient and the wrist of the patient is positioned using a second forcein a counter direction. This restricts movement of the arm, which helpsto position the shoulder. Optionally, the head support is positioned tofurther restrict movement of the shoulder by applying tension to theneck. Combined, the patient positioning constraints 2415 controlposition of the tumor 1420 of the patient 1430 in at least threedimensions and preferably control position of the tumor 1420 in terms ofall of yaw, roll, and pitch movement as well as in terms of x-, y-, andz-axis position. For instance, the patient positioning constraintsposition the tumor 1420 and restricts movement of the tumor, such as bypreventing patient slumping. Optionally, sensors in one or more of thepatient positioning constraints 2415 record an applied force. In onecase, the seat support senses weight and applies a force to support afraction of the patient's weight, such as about 50, 60, 70, or 80percent of the patient's weight. In a second case, a force applied tothe neck, arm, and/or leg is recorded.

Generally, the patient positioning and immobilization system 2400removes movement degrees of freedom from the patient 1430 to accuratelyand precisely position and control the position of the tumor 1420relative to the X-ray beam path 2370, proton beam path 268, and/or animaging beam path. Further, once the degrees of freedom are removed, themotor positions for each of the patient positioning constraints arerecorded and communicated digitally to the main controller 110. Once thepatient moves from the immobilization system 2400, such as when theirradiation treatment plan is generated 2650, the patient 1430 must beaccurately repositioned before the irradiation plan is implemented. Toaccomplish this, the patient 1430 sits generally in the positioningdevice, such as the chair, and the main controller sends the motorposition signals and optionally the applied forces back to motorscontrolling each of the patient positioning constraints 2415 and each ofthe patient positioning constraints 2415 are automatically moved back totheir respective recorded positions. Hence, re-positioning andre-immobilizing the patient 1430 is accomplished from a time of sittingto fully controlled position in less than about 10, 30, 60, or 120seconds.

Using the computer controlled and automated patient positioning system,the patient is re-positioned in the positioning and immobilizationsystem 2400 using the recalled patient positioning constraint 2415 motorpositions; the patient 1430 is translated and rotated using the patienttranslation and rotation system relative to the proton beam 268; and theproton beam 268 is scanned to its momentary beam position 269 by themain controller 110, which follows the generated irradiation treatmentplan 2650.

Although the invention has been described herein with reference tocertain preferred embodiments, one skilled in the art will readilyappreciate that other applications may be substituted for those setforth herein without departing from the spirit and scope of the presentinvention. Accordingly, the invention should only be limited by theClaims included below.

The invention claimed is:
 1. A method for irradiating a tumor of apatient with charged particles, comprising the steps of: delivering thecharged particles with a charged particle therapy system, comprising: asynchrotron; an extraction foil; a charged particle beam path; and arotatable platform, wherein said charged particle beam path runs throughsaid synchrotron and above said rotatable platform; controllingintensity of the charged particles using a current originating at saidextraction foil, said extraction foil positioned in the charged particlebeam path after entry into said synchrotron and prior to a Lambertsonextraction magnet, wherein electrons of said current originate in atomsof said extraction foil; actively scanning the charged particles alongat least three axes, wherein said at least three axes comprise: ahorizontal axis, a vertical axis, and an applied energy axis; during anirradiation period, rotating said rotatable platform to at least fiveirradiation positions covering at least ninety degrees of rotation ofsaid rotatable platform; timing delivery of the charged to the tumorusing a respiration signal, wherein a respiration command is sent to thepatient using a display monitor, said display monitor configured toco-rotate with said rotatable platform, said respiration signal monitorrespiration of the patient; and irradiating the tumor with the chargedparticles during each of said at least five irradiation positions. 2.The method of claim 1, further comprising the steps of: holding thepatient with said rotatable platform during said irradiation period; anddelivering the charged particles through said charged particle beampath, wherein said charged particle beam path circumferentiallysurrounds the charged particles at least in said synchrotron.
 3. Themethod of claim 1, further comprising the step of: rotating saidrotatable platform through about three hundred sixty degrees during saidirradiation period.
 4. The method of claim 3, said charged particletherapy system further comprising an irradiation control module, whereinthe tumor comprises a distal region, wherein said irradiation controlmodule further comprises the step of: terminating said charged particlebeam path in said distal region of the tumor, using control of energy ofthe charged particles, in each of said at least five irradiationpositions.
 5. The method of claim 4, further comprising the step of:said irradiation control module controlling both rotation of saidrotatable platform and said energy of the charged particles toirradiate, with Bragg peak energy of the charged particles, a changingdistal position of the tumor as a function of position of said rotatableplatform.
 6. The method of claim 1, said charged particle therapy systemfurther comprising the step of: distributing delivered distal energy ofthe charged particles about an outer perimeter of the tumor, whereiningress energy of the charged particles comprises three hundred sixtydegrees of circumferential distribution about a plane of the tumor. 7.The method of claim 1, further comprising the steps of: controllingenergy of the charged particles during an extraction phase of thecharged particles from said synchrotron using said extraction foil; andcontrolling said intensity of the charged particles during saidextraction phase of the charged particles from said synchrotron usingthe electrons originating in the atoms of the extraction foil.
 8. Themethod of claim 1, wherein said step of rotating said rotatable platformcomprises rotation of said rotatable platform through about threehundred sixty degrees during said irradiation period, and wherein saidstep of irradiating the tumor occurs with the charged particles in atleast thirty rotation positions of said rotatable platform during saidirradiation period.
 9. The method of claim 1, wherein said step ofactively scanning occurs at each of said of said at least fiveirradiation positions.
 10. The method of claim 9, wherein said activescanning system further comprises the step of: controlling saidintensity of the charged particles.
 11. The method of claim 1, furthercomprising the steps of: focusing ions using electric field linesterminating at metal conducting paths within the charged particle beampath, said metal conducting paths comprising a conductive mesh; andinjecting the ions as the charged particles into said synchrotron. 12.The method of claim 1, further comprising the step of: turning thecharged particles in said synchrotron about ninety degrees using a setof four turning magnets, said set of turning magnets wound by a coil,wherein said coil does not occupy space directly between any of saidfour magnets.
 13. The method of claim 1, further comprising the step of:accelerating the charged particles in an accelerator system in saidsynchrotron, said accelerator system comprising: a set of at least tencoils; a set of at least ten wire loops; a set of at least tenmicrocircuits, each of said microcircuits integrated to one of saidloops, wherein each of said loops completes at least one turn about atleast one of said coils; and timing said accelerator system with aradio-frequency synthesizer sending a low voltage signal to each of saidmicrocircuits, each of said microcircuits amplifying said low voltagesignal yielding an acceleration voltage.
 14. The method of claim 1,further comprising the step of: applying a radio-frequency field to thecharged particles in said synchrotron to yield oscillating chargedparticles, wherein the current is used in control of the radio-frequencyfield; extracting the oscillating charged particles from saidsynchrotron by slowing the oscillating charged particles with saidextraction foil.
 15. The method of claim 1, further comprising the stepof: monitoring both a horizontal position of the charged particles and avertical position of the charged particles in a beam transport pathusing photons emitted from a coating on an output foil, said photonsemitted from said coating when struck by the charged particles.
 16. Themethod of claim 1, further comprising the steps of: generating an imageof the tumor using an X-ray system; and said charged particle therapysystem targeting the tumor using said image, wherein said X-ray systemcomprises a cathode comprising a first diameter and an electron beampath comprising a second diameter, said first diameter at least twicesaid second diameter, wherein electrons emitted at said cathode traversesaid electron beam path before striking an X-ray generation source. 17.The method of claim 1, further comprising the steps of; monitoringrespiration of the patient using a respiration sensor; and controllingsaid respiration, said step of controlling using a signal generated bysaid respiration sensor and feedback respiration instructions providedto the patient provided on a monitor.
 18. The method of claim 1, furthercomprising the step of; dynamically adjusting timing of said step ofdelivering the charged particles to occur in synchronization with achanging respiration rate of the patient.
 19. A method for irradiating atumor of a patient with charged particles, comprising the steps of:delivering the charged particles with a charged particle therapy system,comprising: a synchrotron; an extraction foil; a charged particle beampath: and a rotatable platform, wherein said charged particle beam pathruns through said synchrotron and above said rotatable platform;maintaining a first vacuum in an on beam focusing system in the chargedparticle beam path prior to said synchrotron; maintaining a secondvacuum in said synchrotron, said first vacuum in said ion beam focusingsystem and said second vacuum in said synchrotron separated by aconverting foil, said converting foil converting negative ions intopositive ions, pressure of said first vacuum not equal to pressure ofsaid second vacuum; controlling intensity of the charged particles usinga current originating at said extraction foil, said extraction foilpositioned in the charged particle beam path after entry into saidsynchrotron and prior to a Lambertson extraction magnet, whereinelectrons of said current originate in atoms of said extraction foil;during an irradiation period, rotating said rotatable platform to atleast five irradiation positions covering at least ninety degrees ofrotation of said rotatable platform; and irradiating the tumor with thecharged particles during each of said at least five irradiationpositions.